This is tough. I feel for you
@AndyG. I've had a couple instances of dealing with this type of behavior. The first was one of my best friends in high school. He had crohn's disease and spent most of our senior year in the hospital. He never really recovered from it. Got addicted to pain meds. He bounced around for about 15 more years, addicted to increasingly powerful prescription meds, including oxy. He ended up in jail for a couple years because he stole a 'script pad and was forging Drs names to get his drugs.
He stayed with me a couple weeks after he got out. He didn't have any place else to go, so we set him up with the condition that he gets a job or at least helps out around the house. He drank all my alcohol, then wrote me bad checks to "replace" it. He didn't even look for work, or help out around the house. When I called him out, it was just excuse after excuse. One of the hardest things I've done in my life was kicking him out. It took two weeks between letting him in and kicking him out. He ended up back in jail that night. We kinda lost touch after that. He bounced back and forth with sobriety and not. He couldn't ever cut everything. Alcohol want a drug to him, so it was "different" and didn't count in his programs. He died in jail after a bar fight one night in 2008.
My sister in law has been the victim her whole life too. On disability, never worked a day in her life, prescription drugs and alcohol. My father in law takes care of her taxes, repairs her house, etc. Mother in law get her help from different organizations, please with her to get help from shrinks, etc. She gets drink, calls them on the phone and yells at them with such hate and evil that I don't even understand why they subject themselves to it. This woman attacked one of her boyfriends with the claw end of a hammer one night. She got a couple months of free lodging on the county for that one.
We thought she was was going to die this year. She had dropped off the radar for a couple months, and a friend of her finally got some paramedics in. It took three tries before they admitted her. She kept refusing treatment and was lucid, so the paramedics had no choice. My mother in law tried to get power of attorney even. Finally she was convinced to go for a check up. She spent four weeks in the hospital, and another 6 months in a recovery /nursing home. She finally in her own apartment and actually doing better. But, her health is so far gone that she doesn't really have much quality of life left. Her liver might last another year. I really think the difference is the friends she used to hang with have moved on. She's not a strong enough person to move away from the friends. I don't think she has any remorse or has flipped any switches in her brain to become sober. In the meantime, her old house is in her son's name and it's pretty much a total write off. We talked about having it condemned to get her out of there and into the hospital.
In both cases, these people are the epitome of selfish. They are victims, no matter what. It's always someone else's fault and they don't care who they hurt along the way in their path of their self destruction.
Fortunately, my wife has a healthy distance from my sister in law. She cares, but understands that caring is much different than enabling. The parents are much further along the enabling scale and we've had those conversations. It's hard to argue with them though. Their ultimate comeback is, "That's my daughter, and I'll be damned if she doesn't have a dry place to sleep, hot water, working fridge, etc". You can't argue against that. It's pointless.
Good luck Andy. Know you are not alone.