Sizing up the bowling shoes

Mothers bowled for free last Sunday and so the whole family went bowling (we would of anyway). You have to rent the bowling shoes. Here is my sister's size 7 next to my son, size 15. I don't know the European translation of that size, sorry, but for a couple of years we were buying my son a new pair of shoes twice a year if not more. He is only 15 and stands 6'1'. His father and I are under 5'8"