The following short clip shows him on stage decorating Christmas cookies (He's right in the middle).
This next clip shows Grant saying his line. He says his line towards the end, so hang in there. The boy in the red sweater is his "best friend" from his class. It is hard to hear what the kids are saying, but you can hear Grant pretty well.
Afterward, everyone stayed for a little while to enjoy cookies and socialize. It was a fun night, and we loved watching Grant, and all the other kids, up on stage.