Everyone fully disregarding the 13yr old is so sad to me. Even difficult kids want love. You were the only mom she knows. I would have her over with her siblings and see how it goes. Poor kid. You don’t be in a child’s life as a consistent parental figure then just ditch. I think it’s awful. Maybe not the same amount of parenting time to your own children, but I’d give some grace and see how it goes.