Things went better than expected. My niece (48) is leaving her husband, her house, and her 1 grown son who lives at home. They have 2 other grown children who do not live at home. My DD is sympathetic to her husband and son. I am VERY understanding of my niece - sometimes you need to do what you think will make you happy.
Unfortunately, this is all happening within a year of my sister (her mother & business partner) dying.
The family event went smoothly. No drama. Lots of good food & memories of my sister.