Wedding/ mother in law issues

Feeling kinda bummed and worried about the day of right now. Just wanting some opinions on what some other brides would do. My FH does not get along with his mother. I encourage him to involve her with planning as much we can. She is not very motivated to do much. She works at a store where we recently bought $1-$2 clearance jars for our centerpieces & my FH asked her to look at her particular store for them. She texted him & said they had a bunch. After not being able to get an answer back from her for a few days, she said they only had 1 and it was broken. He told her if she didn’t want to be involved with the planning process to let him know, since it was a complete 360 from a few days prior. She answers back how no one tells her anything, we don’t involve her (we are trying), don’t ask her any of her opinions or take her opinions into consideration, she then mentions a prom we went to over 5 years ago when we were in high school and how I picked his suit color out. My FH is beyond done with her, and is considering not inviting. I just do not want her to come and ruin our day because she thinks it should be about her. Just wondering when I should step in, if I should step in. I usually let my fiancé handle it all.