His wish?

"I wish I could be just like my Dad," Gregory thought as he turned to look at his role model.

Of course, Gregory has no way of knowing that Frederick had once been unsure of his parenting abilities. Gregory had only met his own father once in his life, so he was once very scared to be a parent. But then, Sheldon told him that whenever he wasn't sure what to do, to think of his Uncle Evan.

Uncle Evan raised Frederick as though he were his own son. He and Fiona had always felt more like brother and sister than cousins.

Frederick knows that he never would have gotten as far in life as he has without his memories of Evan.