This sounds like an incredibly difficult night for you and undoubtedly very hurtful.
I can imagine it being all the more wearing after such little sleep too so soon after an op.
On reading your predicament my first instinct was to talk about your eldest sons mental health. Cannabis use asside for a moment, an unstable living situation and relationship issues will be big triggers for anyone, let alone someone with a history of anxiety, depression or mood disorders.
I can only imagine how difficult it may have been for him as a 46 year old man to admit to needing help from his own mother too.
It sounds as though he's still trying to understand life without his biological father in the picture, Speaking from my own experience- I spent alot of my childhood being very angry at my mum, I had lots of questions but didn't know how to ask them and instead lashed out and closed myself off emotionally.
With regards to his accident, did he recieve any treatment -psychological or otherwise- during his recovery? Or did you as a family receive any information or advice on behavioural changes, mood swings or psychological issues?
Alcohol and cannabis use will be a huge catalyst for the above mental health problems to spiral further downward, often leading to such emotional and depressive episodes.
I would approach this from a mental health stance and only after this discuss his drug and alcohol intake with experts, you may find that assessing the former helps conquer the latter.
Is he sober during the day? If so I would recommend beginning to calmly talk to him about this, if he's not willing to talk give him space and try again a while later.
I'd advise trying to find help or advice via here - https://www.mind.org.uk/information-sup ... eone-else/
I'm sorry you're battling all of this so soon after treatment too, I hope you're on the mend and that the above is helpful in some way.
All the best,