Well, a healthy dog won't starve himself to death and a labrador doubly won't ! Labs eat lots, sometimes, it must be said, a tiny bit too much ! if the vet says he's OK, it's odds on he is.
Is your daughter at home with you and the baby? Dogs are funny with new arrivals. When I arrived, some 60 years ago, the dog left home, he was so disgusted, and turned up at the digs my father lived in before he was married, eight miles away, demanding to be admitted ! The dog is aware that he's not getting enough attention and, anyway, his 'rival' is a noisy thing that doesn't sleep. I ask you! What's a dog to do? If you make a point of making as much or more fuss of him as of the baby for a while, and he sees that, his doggy nose won't be so much out of joint. You don't have to do that forever. He'll gradually adjust.