I think it’s kind of gross but if they’re two consenting adults and she (the elderly woman) has all her marbles, my only other concern would be that the guy is looking for money. I would wonder with all the fish in the sea, can this guy not find one a little closer to his age, maybe a 20 year difference if he is into older women?
It’s less common to have relationships with older women and younger men, and usually, when there is, there’s not such a big disparity.
My mother married a man that was five years younger. That’s a fairly minor age difference.
My aunt married a man that was about 15 years younger and he took her to the cleaners, as we suspected he would. She thought he was wonderful, and then he cheated, and when they got divorced he got half her pension and a bunch of other financial benefits, whereas when she met him, he was financially not well off at all.
I’m thinking about celebrity couples – Mary Tyler Moore’s husband was younger, I’m not sure by how much. He was and maybe still is a doctor.