IMO intervention (if that's what it was) involving the two parents and their close friends of the sparring party (ex/husband) could be perceived as extremely bullying. We don't know how pushy or bullish they were about making this arrangement and although they were 'like family to her' their first and foremost loyalty is to their beloved son. I can't imagine anyone is too fond of their son's ex if they've heard all the stories...
We don't know enough about EP or her circumstances but honestly, in dynamic terms, when the opposing party comes into your home with four of their closest allies to 'discuss' (ie confront) a conflict and you are on your own with no other support, that's terrifyingly unsettling. If she was a friend or family member of mine, I'd have insisted she take professional advice and have an advocate and friend with her at the very least.
I wonder if she audio recorded or secretly CCTV recorded the meal? I would!
JMO MOO