I want to see purchase history for a family member I have family sharing

I’m using family sharing and I can’t see the purchases made by another person to see what I’m being billed for. I’m curious why anyone else can purchase when I have ask to buy turned on.

to the point my grandson has used his ability to purchase without my permission and I do not have access to see what he actually bought. The debits have come out of my checking account and still I do not know what was purchased.

He denied it and said he was hacked. I’m sure This is not the truth. Yet in my purchases I only see what I’ve purchased not what he had purchased.

I’m using family sharing and feel I am sharing with them in my family, yet he purchased items that do not appear in my purchase history. And likewise I’d not sharing those purchases with me.

As the head of the family sharing group and the responsible party why am I not shown what I’m paying for?

I’m using iPhone 11

he has the 8