Partner with ADHD has left

So I have been with my partner for 7 years. He is 40 and was diagnosed this year with ADHD.  He goes through spates of surviving and struggling.  He has a cocaine addict which is re inforced with heavy drinking.  The physcologist has told him he needs to drink and he was determined to do so.  However in the past month knowing this information his addiction have become worse. He are constantly arguing about it.  His daughter also for kicked out of her mother's house and has been staying and is causing issues.  This has lead to him walking out on me and getting his own place with her. I know he loves me as the day before we were making plans for our future, which is what we do on a regular basis. I am at a loss and severley concerned for his wellbeing. I don't know what to do for the best. He always calls our house his safe place but he's just walked away.