The best advice that I can offer is not to think that you can or could have made a difference in inspiring the person toward treatment and sobriety because, no matter how hard you try, almost always you cannot. Even professional counselors cannot reliably get those they counsel to get and stay sober.
Look past the substance abuse though and do not stop caring about, spending time with, and being supportive of the substance abuser. They need that, and you do too, especially when a terminal ailment is involved. Talk of better times, old friends, and hope for eternal glory when the sufferings of this life are done.
(Look past the substance abuse though and do not stop caring about, spending time with, and being supportive)
Yes, if possible. And 🛐🛐🛐🛐🙏🙏🙏🙏