Brock is a hybrid.
Usually, hybrids don’t exist in the Supernatural world, or if they do, they’re super deformed and die fast.
Brock is an exception.
He’s a rare Mer-werewolf hybrid.
His mother was a mermaid, she disappeared after his birth, and his dad is a werewolf.
His dad says it was because of his mother’s Mer blood in him that Brock was able to heal and survive and look, well, relatively normal.
Brock uses relatively normal because he’s gotten so many comments about how attractive he is, some of them use “unnaturally” too.
Anyway, it hasn’t been an issue until Petey came along.
But that’s another story for another time.
The main issue is that no one knows Brock is part-Mer, mainly because it’s dangerous and deadly for any non-Mer to know, which is why his dad is having memory issues at the moment.
Another main issue is Petey has been gone, with Quinn, for a long time.
Brock’s body and magic can’t take it.
Brock’s going to reveal or blow up something to the team if it keeps it up.