Hunni, this is the same situation - apart from your husband's heart attack - which you've posted about before. Last time I thought you said that you were going to kick your son out. Sounds like you didn't do that. Are you getting any support? There are lots of support out there. Try https://adfam.org.uk/ as a starting point.

I hate to be the bearer of bad news, but often mental health services won't get involved properly if there is drug/alcohol use as behaviours can often be put on those, rather than mental health. It might be different where you are, but that's the case here.