You know- it might have been totally harmless but what you have is one sulking grandpa and a grand-daughter who is paying the price if she hasn't seen him in 3 weeks. Suck it up and go apologize (you can have your fingers crossed behind your back). If he doesn't snap out of it immediately then play the grand-daughter card---why should she pay for his big sulk. FIX THIS before the holidays. Good luck.