Some health can be purchased with money. Not every health issue can be solved with money, so the rich may be in the same boat with everyone else when misfortune hits, maybe with some fancier doctors around.

People say time is the most precious thing we have. Someone always ill may not see it this way. But rich people can buy some time too. Either through better health, or by delegating/paying others to do for them tasks they don't want to do themselves so they can focus on what is important to them. But when their time comes, it comes, no matter how wealthy they are. Unless they can find ways of becoming immortal.