Boyfriend of 2 and 1/2 years lost his father to cancer on Xmas day - severe depressive symptoms and anger. Now I'm drowning

Meaghan
I am 32, he is 36. His father was his best friend. Grieving is different for everybody and for him is is just this twisted up, severely depressed, severely angry person who I have never seen from him. We went from a perfectly happy relationship with near zero conflict and not even an argument to speak of. Now he is not coming home, drinking heavily, and taking his anger out on me. Not physically, but just treating me like I don't matter, my feelings are selfish, and the worst was leaving at noon on Valentine's Day to "go pick up my gift" than never returning home and only 2 cryptic texts before 6:30 pm. 
I'm losing weight rapidly now, this physically hurts. I got so mad that I transferred his belongings to the living room which I now regret whole heartedly. I feel like I made it easier for him to just walk away. He finally contacted me yesterday when I told him that if I didn't hear from him I would have to call his child's mother to ask if she has heard from him because myself and his sister didn't know if he was lying in the hospital Ina Diabetic Coma from his drinking. 
He finally basically responded and it came down to he needs to be alone, he doesn't want to move you, but he can't drag me down with him right now. He is "deeply sorry" and doesn't want it to be like this but he can't fight the anger and hate inside and doesn't know what else to do but throw himself into work. He states he can't get help because any depressive symptoms can have perminant lasting effects on his career. 
We were so in love, talked of marriage, he was saving for the ring, and now it is as if he has left me. I am now lost, confused, hurt, and having panic attacks at night . I just don't know what to do other than give him the space he needs and not talk to him for a bit... He knows that's the plan now because he agreed it's best. This is breaking me into pieces. Ian watching the man I love, usually so strong, fall to pieces, tear everything we had to shreds, and I don't know what to do.   
 If anyone has any insight please please tell me something. I feel like he won't come back from this.