he's a kid that doesn't understand shit. They never explained to him whoever he was or slowly introduce him to his birth parent. They just suddenly gave him, in his eyes, to a stranger. It's very unfair to him too. It's not a bad idea to let him live with him but let the kid slowly warm up to him. Just cuz he's the birth parent, it's okay for kids to be forced to be with them having never even met them. The birth parent is a stranger. STRANGER. You can't just say he's your birth parent and be okay with it... I repeat, he's a child who cannot comprehend what's going in. He's confused why suddenly, the person who raised him all his life is suddenly "gave" him away. He doesn't know this person, why is the person I love the most is suddenly gave me away to a stranger??? He's in a roller coaster of emotions, he's valid for feeling that way.
Secretly wishing the kid acts up so much the "dad" sends him back....