I absolutely love this idea. Aemond has moved on with his life, and he's sure that his family has too. No one ever came looking for him and he would not have left with them even if they had. He has made a life for himself that he is quite happy with. So when his siblings and their children and their dragons are suddenly at his front door, he's a bit unprepared and confused. His first instinct is to turn them away, sure that this must be some kind of ploy to convince him to return to Westeros but he won't. They surprise him by telling him that they wish to stay with him, if he'll have them.