If I was a covering psychiatrist for an 80 y/o psychiatrist who *supposedly* will be coming back, I probably wouldn't force them change things, in 1-2 visits, but I would counsel the patient that the drug combination that they are on is not standard practice.
I would inform them that should their 80 y/o psychiatrist decide to retire someday soon (a very strong possibility), then their next psychiatrist will likely change their treatment plan because it it does not fit with current guidelines for treatment.
If the patient wishes to start that change now, that I'd be happy to offer that option to them.
I would also inform them that should our visits extend out past 2 months (ie: psychiatrist decides not to come back), I will start making changes for them.
Oh, and I'd get a drug screen on each of these Xanax/Adderall patients before I even get out my prescription pad.