I would let him do his thing with his family & new baby in the family but keep my distance at this point. If anything has really changed....great....let him feel it out. He has a right to be around his family, hopefully he will initially do that in a guarded way to make sure it's ok even for him personally. Let him see how it goes. Family never HAS TO ACCEPT the S/O....though its always nice to be accepted its not necessary..some families are just that way.

Focus on your relationship with him. I doubt that anything will change with that just because he sees his parents again....but keep an eye out just in case....he has a right to see his family if that is what he wants.

See what the future holds.