Family dynamics

I know what you mean. Ive seen this happen in my close friends too. The thing is, you have take it slow. Dont do everything at once because they are noticing things changing and obviously not liking it. Its sad to see this happen because this poor woman is probably so lonely right now.

Dont talk to your husband about this directly because in his mind, he might start to associating you with his mother and you dont want that. Instead, do small things here and there. Dont look for results right away...this is a huge gap and will take time to fill.

Take small steps otherwise you will jeopardize your own marriage and your relationship with FIL.