Really struggling

Im really struggling at the moment, because my SO’s mum has become mentally unstable recently, she has wound up in hospital 3x since February. But the thing im struggling with is that my husband is nit coping very well with how his mother is doing, he’s become uncooperative, and quiet an asshole actually. I think that if his job didnt do random drug and alcohol testing, alcohol would be his every night coping vice due to this. I dont know how to help him and stop stressing myself at the same time