Responses
He's showing "signs of being obsessive"...because he's an emotionally neglected child, and is finally able to interact emotionally freely. Interacting with her gives him no reason for him to question if he's overstepping with his talking, show affection, or accepting affection. He literally even said when the baby's brother and him had a fight that he sees the baby as a little sister that he can dote on. Plus he looks like their the only two in this lifetime that have similar or the same powers, so that's probably another reason he sticks with her.
Also saying he's showing signs of liking her, as in romantic, is wild. He's a child...
As much as I would not like for that white haired punk to be the ML, I don't think I would really like it if the blonde kid would be the ML.... Idk why but he already is showing signs of liking her or obsessing over her which could potentially be carried in the future when our MC grows up. It'd be weird if he was the ML.