Some pitbulls are problematic, some aren’t like most dogs. We wouldn’t have one but I have had friends who haven’t had problems. One question I have about this is did they prepare the dog for the baby? Now they have lists of how to prepare your pet for your newborn - we did a bunch of things to help our cat adjust when we brought out baby home last fall. Things like marking the baby’s socks by rubbing them on the cat so the baby ‘smells’ right. Starting to use baby lotion and powder before the baby is born so the animal is used to the smell. Keeping the animal away from the baby for the first few weeks whenever possible (the dog should not have been in the bedroom), playing audio of crying babies before the baby is born, again so the animal gets used to it. I have other friends with dogs and they prepared the dogs and there haven’t been issues.
I do feel for the parents, this is something their marriage may not survive.
No one should allow *any* dog that close to a newly arrived baby.
The sounds and smells, much more obvious to a dog, can overwhelm the nicest dog in the world.