what they told her is just meaningless doctorspeak drivel for: everyone should do those things, everyone already knows that, youre no different than anyone else, but because we charged you so much money were expected to give you some sage advice.
after the post op period there is no difference between a kidney donor and anyone else who has had significant surgery in the past, except they no longer have a spare kidney and so should MAYBE, depending on how they feel about it (kind of like the risk of hepatitisb vs its cost) be a bit more prudent in exposing themselves to major trauma.