Drug Addict Family Members Money

I have a drug addict sibling who has a history of drug abuse for over a decade. While he was homeless, he got into an accident so i became his caregiver and let him stay at my house in Arizona for a year. He received a settlement for a significant amount of money from the accident and is currently “on vacation” in Michigan (where he came from). In the past month and a half he got a rental “stolen” and spent almost $15,000 on drugs and other expenses. The people he was spending time with took his card and rental car which he reported stolen to the police. We have a joint checking account and he asked me to hold the rest of his money on a separate account. I’m not sure what to do here. He seems to have control of his checking account now but I feel morally obligated to not give him the money while he is in this drug induced state. He has been sending me Venmo requests and I have been sending him money to survive out there but he is asking for thousands a week. I also fear he may come back to my house and threaten me if I give him his money back, since he would have the funds to come to my house. He keeps asking me to do everything for him and it’s been extremely stressful. I blocked him for now because my phone will have 100 calls if I don’t do everything he asks. There is a little over $10k left and I want to put some in a savings account for his son and hold a bit in case he overdoses for funeral costs since he’s been hospitalized multiple times this month. I want the money to go to a good cause instead of drugs and I also want to give it to his son to show good intent on my end. Can I legally do this? I just want to move on with my life and get rid of this money, what should I do?

My location: Arizona

His location: Michigan

Edit: added extra details