The All Stars can only accomodate 4 people per room. The only exception is 4 people with one child under three who sleeps in a crib. Your friend would have to have two rooms with 6 people.
Im not sure how old their kids are but if one is under 3 they could also try a deluxe. We stayed at YC lat Sept and had plenty of room for all of us. We got a great discount from Expedia so we paid just a little more for a concierge YC room vs 2 CBR rooms.