He's not unemployable though.
Just not employable where he wants to be.
There are all manner of !!!!eholes out there that have N reg biz Jets looking for pilots. Which is what I think one of the counter arguments would be if it ever goes to court. Mind you I wouldn't fancy Nigeria either.
This hasn't grounded any of them they can still use thier licenses anywhere else that allows the practise or for that matter in the US if they can get employment visa's.