https://en.wikipedia.org/wiki/Age_disparity_in_sexual_relationships#:~:text=%22Half%2Dyour%2Dage%2Dplus%2Dseven%22%20rule,-Graph%20of%20the&text=According%20to%20this%20rule%2C%20a,to%20have%20originated%20in%20France.

Pretty well known rule of thumb for what is "socially acceptable." So, society in general would say he can date a 43 year old, or older, and its socially acceptable. His girlfriend is 24. Young enough to be the daughter of a 43 year old. He was a senior citizen when she was a minor.

Are you attracted to your kids friends? That's gross. Are you attracted to your grandkids friends? That's more gross. That's this situation.