T.C.
Hi Mary,
A big part of *addiction* is co-dependence. The addict tried to pass off responsibility for their addiction on family and friends.
Her friend has roped her into believing it is partly HER responsibility if he is not successful in his own recovery (he's also doing this with his mom, I guess). In other words: if he's going to stay or leave, it's not really in anyone's control but his own. But if he leaves, he can blame your daughter and his mom for his own failure... and the cycle begins again.
I suppose if it were me, I would make my child go to school, and perhaps in the next few weeks, connect her with a group that can educate her on how to be a *positive* support to people struggling with addiction, so she has better tools to communicate with her friend in a healthy, positive way.
Good luck!
t