lease tell me is it polish culture to for mothers sisters brothers and father in laws to act like this in poland.
I think you already know the answer to that. Possessive over their son yes, I can see that happening, snogging other members of their family in such a way...no.
Talk to your husband, he didn't put up much of a fight when you asked him to stop kissing them on the lips, maybe he doesn't think it's normal either.