It's been a while and things have changed. Dh and ss are both seeing a therapist separately. Dh for his guilt of abandoning ss and ss with his anger - with dh abandoning him, his fear of being abandoned again and sadness about bm death.

Dh therapist told him that in order to help and be there for ss, he has to work on himself first then focus on his relationship with ss otherwise he's going to lose him forever. 

The therapist has said that Ss has basically closed himself off to dh and it's going to take a ton of work and patience for him to lower is walls even a little bit. 

Ss has made some progress as well. There is no nore cussing or yelling from him. He's still distant but he's slowly coming around. Before he would completely ignore dh but he's been acknowledging his presence and having small talk with him(before ss would just glare at him or just leave the room). He's not addressing dh as "dad", he calls him "sir before he would refer to dh by his name. 

What was a turning point, is when dh sat ss down and gave him a whole heart apology. He owned it all. Saying how he made a mistake and should have made for of an effort to be in his life and actually moved back when he promised ss he would. He said that if given the chance to change things he would do it in a heartbeat.  For the first time ss didn't look uncomfortable, angry or annoyed. Dh also presented ss with a signed document saying he is forgoing any and all ties to bm fortune. It all goes to ss: life insurance, bank balances, bonds, rental properties, her company. Everything goes to ss as it should. It looked like ss got pretty emotional as well. 

On Bm death anniversary, dh took ss to bm grave (ss would normally just get his driver to take him) and later presented ss with a picture of bm, when ss was born. Ss said thank you and almost called dh "dad". There was been a lot of progress between the two. 

I'm just happy the ss is starting to let go of all tjat hate and beginning to heal. Dh is ecstatic that ss is slowly starting to lower is guard and seemed interested to have a relationship with him again. 

Since school started still works at Bm' company ,but only on weekends, and normally ss's driver will take him, but lately ss has been letting dh take him and pick him up. 

Here's my little update. Fingers cross that only positive outcomes will occur in the future.