I can tell you are anxious, Clove, but its totally out of your hands.  My youngest GD, in Florida, a sophomore, is supposedly doing most of her classes online. So, it's possible but not your problem.  Lets say the worst happens and she doesnt graduate.  How different would her life be than it is now?   She will be living in Beachtown, not working.  The only difference is that your DH will be off the hook for CS.

THe goal is graduation or a GED.  On time.

Beyond that, do not over think this.  A D is as good as an A for the goal that is at hand.

Cs get degrees. Ds get diplomas.  A diploma or a GED cert is the goal.

That said, I did my undergrad engineering degree at a brick and mortar school.  I did my MBA online.  Both were an insane amount of work. Online just as much as brick and mortar. Even more challenging when you consider that no one is taking attendance, turning in work does not happen under the hairy eyeball of a teacher  (Prof) or a TA, and if daddy and TT are not forcing PS to live under the hairy eyeball of school work oversight... she in all liklihood will not finish HS. 

If I were daddy, I would look at forcing a GED test out program to ensure that I am out of the CS business on schedule.

I would not get into it with PS at all. Just tell daddy that she is off the marital payroll on time.  18 or graduation whichever is first. If that is the rule in your State. If not... she fails to graduate on time, drive for forced emancipation.

No quarter.  

That said, I was on the 5yr plan for HS. I had 2 sophomore years.  Then, I was on the 11yr plan for Undergrad.  If I had been a Skid, I would have been so screwed.  Though for undergrad, parental support was for the first 2 and the a portion of the last 2 years. I covered the rest.  

Part of our position with SS was due to my experience in HS.  Fortunately his mom and I were in agreement.  

Take care of you CLove. Do not put yourself through more tension than the goal warrants. Beyond Ds. Grades do not matter in this situation.

It is nerve wrecking when you hear those Skids say they don't want to finish high school. All kinds of thoughts like am I having a lazy ass couch surfer money pit adult living in?

You make sure SD gets at least a GED. So at least can get a job later.

Your bio mom friend... must be lucky with her step(s) and the BP must have given her authority to raise them. Easier said than done.

My niece changed to online classes to finish high school due to a lot of personal issues going on that were effectively making regular school very problematic. 

She ended up graduating, barely. It took a lot of self study and discipline which she didn't really have, and there was a huge lack of oversight by her parents. Skated by.

She's now in community College, but much of the online high school classes didn't count as enough background. She's had to take additional tests for enrollment and has several makeup classes to do for pre-requisites.

Bottom line, it's not easy, and will not help her all that much. However she may be able to eek out a diploma...Clove do NOT get involved. The only thing you need to be doing is making sure your H knows she will not be living with you after graduating or flunking out, or quitting school.

I know it is as hard as you as it is for me to not say anything. But you have to start trying.  I have found out that me saying things about the kids just causes me more agony. 

Whatever the "graduation" date should be, stand on that. Focus on what life will look like after that REGARDLESS if she graduates or not. What are your expectations? No long weeks of visitation? No more money being handed out? Crap behavior no longer tolerated in your home??? 

Figure out what you want and make sure your DH knows there will be NO compromising.

I have some very personal experience with this.

1.  Kids will need an adult who is obligated to oversee and monitor their work.. that they are doing the work.  who will that be? praytell?  In my case.. it ended up being ME.. and THAT was a complete disaster.. trying to manage it mostly from a remote distance.. (SD lived with the Inlaws.. but they refused to monitor her work and husband was working offshore with no reliable access to phone or internet).

2.  THE COST... even if the classes may be somewhat free..there are often materials that must be purchased.. I believe we ended up spending almost a thousand dollars on books etc.. about 9 years ago.

3.  SD's aptitude/abilities.. Look.. if you already have a kid who is doing marginal in school.. being lazy.. procrastinating.. this absolutely will be a disaster... I see ZERO chance of this working if anything you say about your SD is remotely true.  My SD was an honor role student.. but she struggled with time management.. because she had no one to direct her day.. and she spent hours on snapchat.. not doing her work.. it took 2x as long to get through the classes as she originally said it would take.

4.  REALITY of it working?  Well.. we also discovered when she was part way through.. that oopsie.. there is one more class she had to take.. at yet another cost.. so what she thought it was at first.. turned out to be more.. more time.. more money.. more aggravation.

Bottom line is that the chance that a child who has been lazy about attendance (no diagnosed conditions.. just vague malady complaints right?).. who has been lazy about turning in assignments on time for anything.. even courses she likes like ART? .. Who resents anyone looking over her shoulder.. putting a boot in her behind.. gets accused of abuse.   She will bomb out of remote work.

I guaranty that the reality is that she is probably having some social issues at school... and stress over not doing well.. and she is trying to opt out of the experience.. vs buckling down and actually doing the work.  

I mean.. remember..you are married to a guy that can't even figure out how to log onto a school portal to check progress even when he is given full instructions on how to do it.

He won't be able to monitor her.. it will fall to you.. CLOVE will be ENEMY number ONE.  

I know you are disengaged.. but I would tell your husband that this is the stupidest scheme they have come up with yet.

I'll give you the answers they'll give you if you have a sit down.

remember these ate their answers not mine. 

1. whose idea was this? What needs to be done to sign off on this?  I/we am/are the parents, this isn't your bees wax, butt out. 

2. What is the current plan? none of your business, she's my kid not yours. stop trying to control her.

3. How does this get set up? keep yourself out of our business

4. What is your plan for after graduation? Daddddddddeeeeeeeeeeeyyyyyyyy she's scaring me and trying to kick me out of our house. She's mean and I hate her and you need to protect poor wittle meeeeeeeeeeeeeeeeeeeeeeee

1. whose idea was this? What needs to be done to sign off on this?  Really doesn't matter too much who's idea this is.. but I'm guessing that your SD is the one who cooked this up.  Her guidance counselor will likely be the one to manage getting official school approval...and setting out the course requirements.. (that will have to come from approved programs online).

2. What is the current plan?  The current plan is for her to sit around all day.. procrastinate and not finish her degree like she claims she will.. oh.. I mean.. what are they telling you the plan is?  .. that is to take X online classes and then graduate with her class.

3. How does this get set up?  hahahahaha.. you will do it. you will pay for it. .you will manage it.

4. What is your plan for after graduation?  that's not part of this discussion really... that is something your husband should be able to tell you.. but he won't.. cause he is lazy parent no 1

As long as she and your husband know that she will not be living with you, it's not your problem.  I know it's hard.  It seems like the parents don't care.  You can't help but care about her and worry that she will try to move in with you permanently.  Who wants an unemployed adult skid freeloader living with them?  Nobody.  

I doubt she'll graduate.  I hope I'm wrong.  It takes discipline though, to be able to do online classes without parents or anyone who will hold them accountable.  Her parents don't care enough to do it so in all likelihood she'll fail.  Again, not your problem, as long as everyone knows that she won't be crashing at your home.  She can stay in Beach Town and be Toxic Troll's headache.  

You have no control over SD. and what SD does. DH just repeat what his DD is telling him. You know it BM delusional and dysfunctional house no learning will take place.  The school wants SD gone.  They want to stop spending money on her. If she does some school work. They will pass her just not to have a bother drop out.

 
 Your main concern is the future. To stop paying CS  after graduating.  To get SD out of your house and take her dysfunction with her.  Community College as long it's not costing you money.    To let your DH if he continues to pay for his kids. Then he needs to get a second job to fund this.  You will not pay for this for the rest of your life. Because that is in the cards 

Powersulk has been a major truant, with some knarly grades in important classes. The reason, she states is that she has been having migrains, fatigue and nausea.

Today, Husband related to me that she would be completing her senior year online.

Is she pregnant?
 

Not that  I need to know but I'd get an answer to this before agreeing to anything in her terms - which could be the gateway to permanent freeloading roommate/3 generations in one house/inadvertently disrupting your retirement to become free built in babysitters