Hi there. I'm just going to say welcome to DWD.
Just a heads up on antidrpressants, they can take from four to six weeks to get into the system and start to work. I can understand why your boyfriend stopped taking them before if he thought they weren't working.
It can be very difficult when someone is going through a depressive crisis because sometimes it can last just a few days or other times it can last months. There really is no telling how long it's going to last.
Your boyfriend has really done all the right things, going to his doctor and starting in the meds. The therapy will also help but again it takes time.
I think it is perfectly normal for someone who's depressed to withdraw from everyone around them. If you have thoughts in your head that you are useless and worthless, sometimes it's easier to pull back from people to avoid hurting them too. For me, it's almost like I think depression is contagious and I don't want to infect anyone else.