Weddings can be a minefield. I'm sure I'm not the only person who would say that a manipulative parent is the last thing you want throwing into the mix. I'm another one who would call her bluff! If she cuts off communication because she can't get her way, there will only be one loser. Let her know it. My son and his first wife only wanted a small wedding. They had four of their friends, four of her family, four of our family and that was it. Very comfortable for the bride who was not big on family gatherings. However, we held a party for wider friends and family in the evening. When he got married a second time we left it to them to decide who to invite, but it was an altogether bigger affair.