I normally come here regarding DH younger set of kids. 

Today is different, he also has two older children (different BM) UGH I know.  I'm just venting I suppose. 

Anyhow for a little background, Eldest SD is getting married soon. He has been divorced from her mother for 30 years. Her sister and DH have been estranged for about 10 years and although he has attempted to reach several times, remain estranged. 

Eldest SD wedding is fast approaching. We haven't seen or spoken to their mother since the younger sister's high school graduation. Not long after is when he and that daughter became estranged. 

Eldest moved to our state with her fiance last year. Stayed with us for a couple months and was able to find a rental nearby. We have a pretty good relationship her, her dad, the fiance and I. She has always complained about her mother but I also know how kids (she's mid 30's) can play both sides at any age, so my guard is always up. For them most part though, she seems very annoyed with mom often and sister even more often and will vent to us. We are careful to listen and DH tries (emphasis on tries) not to add to her commentary with his own feelings. 

Lately as we are super closing in on the wedding date, she is sharing more and more frustration with how the mom is acting. Originally it was more about the sisters comments about "why does dad have to be there" kind of ridiculousness. Now it's also the mom saying things to her like "who is gonna be at the rehearsel dinner" and when she is told the list that of course includes her dad and I she is getting sighs and comments etc from the mom. Last night I told her if it makes her life easier, not to worry about our feelings and we are happy to bow out of dinner after the rehearsel. She was adament that she wants us there and if mommy has an issue mommy can not come.

I feel bad from eldest SD, but no way would DH or I ever circumvent her and say antything to the mom. We are keeping our noses clean and being angels but it sure is sad this woman can't get over whatever issue she has from 30 years ago for one dang day. 

Fingers crossed BM nor the sister ruin this kid's day. They sure know how to be a black rain cloud everywhere they go.