((((Raee)))))
Welcome to PC!!
I can see how difficult this relationship has become for you. It is a very sad and hard situation to be a part of.
I would recommend that you become friends with this guy, instead of bf/gf. #1.) You'd be focusing upon your studies in your senior year (hopefully). #2.) You can still be a friend to your bf & he sure could use one in his corner during hard times! #3.) You don't have to become overwhelmingly involved with the family, to where it's making you emotionally uncomfortable. #4.) When the time comes where you may need to move on to another area, for job or study, the lack of commitment will make it a lot easier. Phone calls and e-mails can still be made between you two, regardless of miles.
That is my personal opinion. It may not be an easy break for you to make, because your bf really does sound like a good guy.

But, staying friends could really help him emotionally ~ because there will be those times where he feels frustrated and angry, guilty for feeling this way, and envious...wishing that he could have gone towards his goals in life like you have. Trust me. Those are hard times to feel inside. Especially if he holds resentment towards his father for holding his mom down and making her become so depressed in the first place. There are a lot of emotions that your bf ought to work through, with a T, to help him work through what's happening in his emotional world.
Very best wishes to you! Gentle hugs....