Bubbles...Your safety is very important!

You mentioned earlier that he said he would "rather live with a foster family". Which is probably being said just to make you wrong. But perhaps there is an Agency in your area that could arrange a foster family (or something similar) situation for him. Sometimes being in a totally different environment can bring changes for the better. I would definitely check that the medication he is on is actually doing him good.

You have taken the responsibility to take care of him this long, which in my opinion is very courageous.

Now you need to put yourself first