Eddiebuckle

Personally, I would never contradict a physicians instructions. The Big Book is pretty clear on this one: leave that stuff to the experts.

However, as to your original question:

Because sponsors can only give their opinions and suggestions based on their experience, and to "order" a sponsee takes away the sponsee's responsibility for their sobriety. You alone own your sobriety, much like it's no one else's fault that you became addicted in the first place.

I recently had to let a sponsee go after he relapsed again. He only seemed willing to work a program when he faced consequences from his relapses, and as soon as things started to settle down started missing meetings, spending time with people who were not supportive of his recovery, etc. When I told him I could no longer sponsor him, he couldn't understand why. I told him he needed to find a sponsor whose suggestions he was willing to follow, and that his actions made it clear that I was not that person. I cannot make someone else willing, and it is a fools errand to work harder for someone's recovery than they are willing to do.

If you don't want to follow the suggestions you get, find another sponsor. If you want the kind of sobriety someone else has, don't be surprised when they suggest you do what they did to get it.