I seriously doubt anything came up in the last 3-4 months that warranted inclusion on the no-fly list. He was here in NY in May, then flew to Los Angeles right afterwards, so he wasn't on any list at that time.

I can see how a mistake could be made since it looked like his name could easily be mixed up (Yusuf vs Usef). It would seem to me that if it was a mistake they would have detained him and then let him continue on his way to Washington. They let his daughter go on, but kept him overnight and sent him out of the country today. For some reason he is no longer welcome here.