No FaceTime icon next to one of my contacts with an iphone?

I just purchased my first iPhone last week (the 6, 16gb) and I transferred all of my contacts over through my gmail. Previously I had a regular old Android prepaid phone. Anyway, all of my contacts that I had backed up transferred over through the settings, and all of my contacts that I know have an iphone have the 'FaceTime' icon under their contact info, except for one. He is an iphone and I simply am unable to figure out the problem!

I have gone under the settings, then to Facetime, to make sure Facetime was on. I also had him do the same thing.

When I make a regular phone call to him the Facetime button is illuminated, but when clicked, it says that 'Dad' is not available for FaceTime.

BUT until today when a regular phone call was made, the Facetime button wasn't illuminated at all. Any ideas?

Thanks for the help!