Passing around baby

Hello!

Long story short.. my husband and i are going to my in-laws for thanksgiving. He has always been super close to his parents and family so it’s always been great. We had a baby 3 months ago and they are great with him. However his dad has disrespected our rules before by saying “I’ve always kissed babies” and attempting to after we stated we didn’t want him kissed. Now his parents are in a thruple relationship and the woman has moved in. My husband stated to his parents of course they do what they want it’s their life but that he just didn’t want to be involved with her. Because to him it’s a stranger. We’ve only met her once and she came on very strong to my husband trying to seek his approval too strong, too early. She also messaged him on Facebook the other day with a statement insinuating that he was doing something wrong by not asking questions. Essentially, he feels as though she’s rushing it and he’s not comfortable with her jumping in as a third parent when he’s already a grown man near 30. My concern is that she’s going to feel as though she’s my child’s grandparent and has the same access that his grandparents do. I’d prefer her not to post pictures of him on social media which she has already done with other kids in the family, and not to really hold him any more than any other family member would. Is this a rational boundary? Or what would you do in this situation.