I would say that is an individual choice. Yes the book states no sleeping in bed because that makes the dog your equal and you need to be Alpha.
Buddy has been sleeping with me for 2yrs. The first year I spent loosing sleep and trying to keep him off the bed! He won. He, now, is a sound sleeper and does not move until I do. If your baby is trained and will not go potty in the bed I would let him stay. He just wants to be next to you and be cozy too.
Rules are made to be broken
Carol & Buddy