Did he have a compelling reason to keep her on it? If not, it can't hurt to ask him how to discontinue it. Ethically, if you tell him you want her off it, he should tell you how to do it safely. And he may have a specific reason for leaving her on it...
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."