He wouldn’t look that good at 64 years of age, if he were still drinking Margaritas non-stop. Looks like he actually takes very good care of himself.
He looks quite robust.
While the "product" he sells is the beach bum lifestyle, Buffett, on the personal level, must be ( and has been) a highly disciplined and hard working businessman with traditional middle class values. If he weren't, he won't be enjoying the success that he has.
My husband and I have been to two of his concerts in Las Vegas. They were a lot of fun.