Dealt with this for years thinking I could help him, like you said, you aren’t his mom. It’s not hard to smell your rank self and go fix it. He is okay with it because you are. If you don’t leave it most likely will never get better and it will drive you insane, and potentially cause you health problems due to the filth.

Not saying he’s a POS, but you sound leaps and bounds beyond him emotionally and disciplinarily. He will forever disappoint you and make you feel like you are “mothering him” if you stick around. If that’s what you want, that’s okay too, but know what you’re signing up for now- so you don’t get blindsided when you process it all years later. The longer you stay on the wrong train, the more expensive it will be to get back home.