How to convince a friend/co-worker, that he needs diapers

I have a co-worker who admitted to me that he sometimes wets in his underwear. He also confessed to me that he often wears two pairs of briefs and lines his underwear with washclothes and paper towel. He claims this solves the problem, but i think he is fooling himself. I wear diapers and see no shame in it. How can i convince him he needs better protection.