How do you translate the -seru conjugations?

Question:

I'm having a hard time understanding this because I really don't know who had who do what.

あ~ジョンならK-Pop聴かせたら一発で寝るよ

I'm getting "Uh...If it's John, he'd have you listen to k-pop and you'd sleep in no time"

Answer:

あ~ジョンならK-Pop聴かせたら一発で寝るよ

"Uh...If it's John,
you would have him listen to K-pop and he would sleep in no time."

is the right answer.

"he'd have you listen to k-pop and you'd sleep in no time"
is wrong.