Sorry if this is long winded as don't want to drip feed.
Bit of background, DB (30) is clever, funny very practical and is loving and generous. He has always lived a transient lifestyle and relied on my parents to some extend and struggled with drug use in the past, sometimes heavy which I think has contributed to some underlying MH issues which haven't been addressed. As a result he has moodswings, generally feels the world owes him something, has a disregard for other people's views and can't seem to see what is acceptable behaviour so is very hard to live with.
Just lately his anger has been irrationally directed towards DM, and were all treading on eggshells around him.
Parents in the past have tried to help and have supported him but he has avoided any professional advice. With parents help he got qualifications and managed to get a well paid job and things were looking up for him.
Then recently it all went wrong, he has given up his job, been evicted for not paying his rent and has no money in the bank and now seems to have decided to move back with parents. He hasn't asked them if he can and isn't contributing anything to household. Just stayed one evening in his old room, which he did occasionally anyway, and hasn't left. He avoids all conversations about it and just makes himself scarce whenever it's mentioned.
He is obviously struggling with life in general and seems to have lost interest in everything. On top of the many issues, parents are due to go away for a month, they obviously don't want to leave him without anywhere to stay but also don't want to give him keys and money for food, which is what he would need.
Poor parents are in despair and don't know what to do... Any advice welcome.