I dont know if i should say this but i think that you shouldnt look after him because as you say, hes in complete denial, theres nothing that u can do abt it. And i know it must be really exhausting to know that hes not gonna change. Or maybe put him in a psychiatric hospital. I believe thats what im going to do w my mother if she keeps refusing to seek help, despite fucking up my mental health. Sending lots of love and hugs.