If he's hosting just some textfiles (i.e. a few KB), he won't have any aws bills that he would need to worry about prepaying. (I have a static s3 website, low traffic and low storage size, and i have not paid anything on it for years).

At least that's the case today, but the policy may change tomorrow. It's not easy to guarantee anything 10 years from now, let alone 100 years.