My granddaughter is having a had time fitting in her new family.?

There are two other children and she is the oldest(she's 10). Her Daddy is pressuring her to do the conceding so that everyone else will get along, especially the new Mommy. I want to tell him that the new kids are brats and that if he would step back and look at the situation from the out side he would see that. But he is blinded by love, and my Granddaughter is miserable. What can I do?