I just answered a different question about his parents (they're dead lmao), but he has a great relationship with his younger sister! (who is one of Bees' ocs)

After their parents died, Gael basically had to raise her instead of being able to study to become a teacher, but he doesn't regret it at all. He's very protective of her, and would've done anything to make sure she got to grow up and have a normal life to do what she wants with.