Let him fall on his own sword. His problem, not yours. He's almost 18 and will be facing many more adult situations in this world.

I'm going to have to agree with HRNYC. I'm a tumblr user and we see these "fakers" all the time. It's drama. They can hide behind a computer screen and be any persona they want. Relatively normal for a section of the teenage population that are attention seekers.

Craving some attention it sounds like ...

He's healthy, he doesn't show symptoms of anorexia or bulimia right? Forgetaboutit.

I agree it sounds like an attention issue. That said, I would go do your research and make sure there aren't actual signs of some sort of eating disorder...bad breath all the time (usually from purging), shallow skin color, hair loss, etc. Also, the next dental appointment, you can take your dentist to the side and ask them to check for thinning enamel which is common if they are purging, as the stomach acids eat away at the teeth. Just say you have a suspicion, and if you are wrong you are wrong. He could be lying about the whole thing online for attention, or he may have other issues.

SD15 has a very unhealthy relationship with food...she goes through stages of starvation, binges, etc. During her binges, she has a habit of disappearing to the bathroom right after or during a meal, and she will be in there for like 10 minutes. If she disappears during a meal, she will come back and say she is done/full. Her breath is so bad all the time...if she is talking from the back seat of the car, you can smell her breath in the front seat. Her hair has been thinning, her skin color is very shallow looking, she is cold all the time, sleeps all the time, crazy mood swings, injures easy and takes forever to heal, irregular cycles...all the signs...but DH doesn't do anything about it! It is pretty sad. She has been on an all out junk food binge since she and the now-ex broke up...claims on her social media that she is so depressed and doesn't know why she can't kick it. BM is bipolar...so it is very possible that SD15 does have an issue. I have tried to bring this up to DH...even recently trying to show him what she is posting to social media, but he still does nothing.

When his followers get bored he might start a new one about being a girl trapped in a male body... Then a month later it'll be about world of Warcraft or emo shit... Months later he's a recovering drug addict, another month later he will be a 60 year old swinging ornithologist. Teens can be strange. And online they can be anyone - freaky. Role playing for attention.

Shame they don't think about future employers googling them!

Eating disorders are serious. You should leave a page open about them, many tabs open. Imply that you've been researching and were interrupted. See if that impacts on his behaviour.

Haha I like the advice by the two OPs directly above this.

SD15 is doing the EXACT same thing...claiming to be aneorexic, bulimic, suicidal, and bisexual. She is truly none of these things. Believe me. Its all about attention whoring. She needs more attention than my toddler. its annoying and ridiculous. She lies about EVERYTHING. So stupid.

The sad thing about this day and age, is that the internet is an open venue for these teens! They don't have friends at school, or feel they aren't getting enough attention at home, and they take to the internet with their problems, or in many cases, total lies to gain attention from their "followers". This only feeds and enables them!

SD15 has been on a total depression thing on her social media ever since the breakup with the now-ex...which I find some things totally strange. I mean, neither she nor the "now-ex" have changed their relationship status on Facebook. On his part, it looks like he hasn't been on his Facebook, but she has been on hers...so why not change the status if you are no longer together? At the same time, you look at her phone records, and she is still texting him constantly! You go over to her Instagram and it is, "Why can't things just go back the way they were" or "I don't even want to live anymore!" Now, I do know BM has had some issues with codependency, and she is bipolar. I'm thinking maybe SD15 has some mental instability, as well. Sad thing is DH is doing nothing to address it!

I believe this type of behavior to be a side effect of the esteem movement. So many kids these days are told that they are special so often for inane crap that praise is like crack to them. They often resort to lying and manipulation to feed their incessant need to feel special when in reality there is little about them that is special. Even the truly special ones (straight A's, kids of character, etc...) fall in to this trap periodically when they see the worthless POS little praise mongers getting the "how special they are" lip service for absolutely nothing.

My guess is that your SS is feeding his esteem habit.

Bare his ass on his bullshit and let him know that trust is earned by being trust worthy. One lie and trust goes out the window. His fabricated world of anorexia is nothing but a huge lie and now there is no trust. He sounds like a good kid so I would nip this shit in the bud pronto before it jeopardizes his longer term behavior. Have him explain how he would feel if his on line minions found out he was completely full of shit. Then ask him why he needs this fabricated bullshit world.

IMHO of course.

Good luck.