Originally Posted by
asking
I totally agree it will create tension not to shake hands, but that is what abusers do--create situations where if other people don't cave to them there's tension or difficulty, something they can complain about. This is a perfect example. If Rome refuses the invitation, he's insulted the ex and he and his parents can be offended. If he accepts and goes, but doesn't shake hands, he's insulted the ex. Same result.
When he gets there, the ante may be upped and Rome could be asked to do something else he doesn't want to do--eat with them, look at old pictures, something weird. It's a slippery slope and all of it involves doing things Rome doesn't want to do.
As for the girls, I think it's unlikely that things will remain civil for long no matter what happens. We already know what kind of person the ex is. It's very rare for such people to change. The best you can do is minimize contact and politely refuse to be coerced or manipulated.