buck and doe raising babies

Question
My rabbits are from the same litter and are kept together because if seperated the buck would not eat or drink he pinned for the doe. At just under 5 months old I had the buck neutered, and put them back together when he can home to my surprise a week ago when cleaning out there bottom bedroom I found that she had babies (at this time the babies were about a week old as their eyes were not open so I checked each day so I could find out when they were born). Over the years I have had serval rabbits yet I cannot get over the fact that both the buck and doe are raising the babies together, when she goes to eat she makes noises at him and he goes down and sits there watching the nest. I always thought that if the pair were in together the doe would kill the babies.
Next stop for me is the vets to get the little ones checked over to make sure they have no abnormalaties
Have you ever heard of this happening before

Answer
I am 100% sure that they have no abnormalities. Rabbits are not like people when imbreeding. I myself breed brother to sister and son to mother all those kinds of combos.
I have not ever heard of this happening, but my guess is it is because he is neutered. He has no reason to kill the babies, because he has no urge to breed the female. An unaltered male kept with a female and babies will definatly kill them.
Samantha