Husband has been drinking a lot lately

My husband has been drinking constantly the last few weeks. My step son would have been 25 now but when he was 14 he was beaten up and died in the hospital. He was best up for being gay and one of the boys who did it(well men now) just got approved for parole. My husband did therapy for 6 years but I think the fact that one of the guys is getting an early release is setting his progress back. He cussed my mom out because my mom tried to "help" but wasn't being helpful at all. My mom's opinion is they were young and shouldn't have their whole lives ruined. They were all in high school. My husband through something at my mom and yelled at her asking why shouldn't they have their whole lives ruined when his kid is dead and never coming back. I had to make my mom leave because honestly this isn't something she should be giving her opinion on. His drinking is starting to get out of control and I'm trying to be there for him but I'm worried this is gonna get worse.