Who's your Daddy?

Conversation this morning in the car on the way to work:

Busby: I need to call Daddy's Mom and Dad.
Me: Oh really? Who are Daddy's Mom and Dad?
Busby: mmmmm.....
Me: Well, who are Daddy's Mom and Dad?
Busby: Papaw and Grandma.
Me: Very Good! Who is Mommy's Daddy?
Busby: Pop!
Me: That's right. And who is Mommy's Mommy?
Busby: Aunt J.
Me: Ummm.....
Busby: No! Your Mommy is Grammy! Aunt J is your sister. I was making a joke. hahahahaha.
Me: That's funny!
Me: Aunt J is mommy's sister. Who is mommy's brother?
Busby: Daddy.
Me: Ummm.....No. Daddy is Mommy's husband.
Busby: Daddy is your husband? Who is Mommy's wife?