My Therapy Couch

My boyfriend of about 4 years is severely depressed. He has a child, and the mother is keeping the child from him. He hasn't seen his son since Mother's Day. It affects him every day, and he missing his boy, and he is always in pain and often projects his pain onto the people closest to him. I just want to be supportive and show him I care and that I love him so much, but he often gets angry at me simply for saying so. I don't want to come off as if I know how he feels or that I know what will solve his problem because I don't know those things. I just want to be helpful, but he even responds to my kindness with anger often times. I know he lashes out because he's in pain, but every approach I've tried seems to fail. Does anyone have any advice on how I can show him I just want to be supportive without offending him or making him feel attacked?