Need help on inbred puppies...?

We just found out last night that my lil sisters weenie dog is pregnant. The only possible father of these pups is her 2 year old son who comes over to visit sometimes. Will the puppies be ok? If not, what complications can we expect? We literally found this out late last night thru the emergency vet & shes gonna be due any day now! Only serious answers please, I'm not here argue w/anyone about morals. We honestly had no clue she was pregnant & tried to keep a close eye on the son when they were together. And yes we will be taking him to get fixed. Thanx!!