If a party have done so much drugs that they presently suffer long-term brain injure should they be told?

hes so bad that even he can no longer function or purloin care of himself on the other hand his family tell him hes perfectly typical that theres nothing wrong next to him Why?If a party have done so much drugs that they presently suffer long-term brain injure should they be told?
To spare him unnecessary grief?
Or maybe they DID inform him, and he just didn't "get" it, and you don't know roughly speaking this?
If he can't function or take precision of himself, he either know, or is too impaired to know.