In the case of health, I can see how having too much money can potentially be detrimental. If he tries hard, he can find doctors prescribing unnecessary pills or surgeries.

I sincerely doubt he has to try hard at all.

I naively think that the best doctors (that he has access too) would do what's best for the patient and would push back unreasonable requests.

"The best doctors he can afford" != "the best doctors he's willing to listen to".

Consider for example Steve Jobs: despite his wealth, he resisted his doctors' recommendations for medical intervention for nine months in favor of alternative medicine.