Iirc, he’s not even Papa Palpatine’s real son - he’s a separate three-eyed mutant who claimed to be Palpatine’s son as a way to grab power post-Endor. The real Palpatine’s son was also a three-eyed mutant, but his third eye was in the back of his head, and his name was Triclops.

I guess people aren’t very subtle with what they name their kids in Star Wars.