This isn't strickly etiquette, but I can't see anywhere else it could fit. I'm in a bit of a pickle. My FMIL is ramping up her opposition to our wedding plans and now threatening not to show up because our plans "aren't good enough." She doesn't like the fact that FI and I are making the decisions about the wedding or that we are doing a lot of DIY. We are paying for this ourselves, and can't afford (nor do we want) anything fancy. Last week she believed that my mom and I are making all sorts of wedding decisions together and excluding her. This week, I'm controlling everything and not letting anyone else touch the wedding. I honestly could care less about anything other than marrying her son - I didn't even pick out my own wedding dress!
FI is going to have it out with her on Saturday over the emotional abuse. He's just unsure as to where to start or what to say to her. She's already been told to back off by her mother but isn't listening. Does anyone have any suggestions as to how he might approach this situation?