Sounds like your boyfriend may need counseling and a friend more than a girlfriend right now. And 3 months sounds like a rather short amount of time to know you have a future together, especially if he is dealing with such a complicated situation. But I believe you can really care about a person even if you have only met them once and if you are willing, I think your bf could just use some support.
I hope that you can support him and give him the time/space he needs. I think others have given you some good links and info on grieving and relationships, maybe the best thing you can do is point him in that direction. When someone is depressed or grieving, it's hard for them to point themselves in the right way.

I hope that you also have some support for yourself, as you are in what I would call maybe a bit of an awkward situation. We are here, you should keep us posted.
*hugs*