Father’s Day plans ruined 😒 this is the last time I’ll ever do something nice for someone

My brother has a 4 year old son. He’s a single dad so I thought I would pick up a small gift and card on behalf of his son and give it to his son to give to him tomorrow. So I bring my nephew up to my room and he’s really not a nice kid. He’s rude and talks back and doesn’t listen at all. I thought it would go well though. But nope. I was wrong. I told him it was a secret and that he has to sign his dads card. “I’m not signing the card. I don’t want to. I’m not doing that. I’m going to tell my dad.” I know he’s a little kid but it pisses me off. He’s such a rude child. I try to be so nice but sometimes I just want to tell him he’s a little brat who doesn’t deserve half the stuff he gets.