Teke, I think he's playing the "guilt card" because that helps stall facing that this is HIS problem and not yours, and he knows that guilt is your vulnerable button right now.
It's hard doing the right thing, but it's still the right thing. He may want to see his doctor and talk about this, if it's depression. Whatever it is, just isolating isn't going to help it. That's good for a short time, but the time has come for him to take better care of himself, and what you did is very loving.
It's okay to not take on the problems of others, especially when they are not willing to help themselves.
Hugs