I had a loved family member who required emotional and financial support for a long time. It was draining. In the end I had to walk away and leave other people to sort the problem out, most of all the person in question had to take responsibility and sort themselves out - whether they were SN, mentally or physically unwell. & do you know what? They did!
Once I stopped being there it is amazing what happened. Everyone else rallied around a little and that person pulled through. & yes they worked again. not at the same level or in the same area as before but they did work again and they did support themselves again.
It was a relief. I made myself ill taking it all on and worrying.
So, do you have access to a counsellor you can go see to help you make a plan? It isnt fair that you take on the worry and care of another adult - it doesnt matter if it is a parent, sibling, child of your loins or best mate. Adults are adults, no matter what their problems.
I found a counsellor really helped. I actually went to the counsellor to help me with my insomnia and recurrring illness. The actual cause was this other problem. Took me 6 sessions but I did loosen the apron strings over that 6 month period and was much healthier and happier for it. So was that other person.
I am not saying your situation is the same but explaining what helped me to see if my story can help you in any way.
best of luck. moan away but probably best not to post in AIBU if you want gentler responses!!!