I don’t see how she would have fared any better if she had waited. If after all she’s already described, the husband isn’t seeing that his mother had the wrong position. What would make this any different? You might think that if she keeps giving in things would get better but nothing has changed for the better in years. From what I’ve seen in examples family/family friends, it’s very important to take a stand with something. From what I know of this situation, the party was a great first step. The next step is to show that the emotional blackmail will be ignored and have no effect.