There's every chance he could. A lot of people say that it's been removed from Xur's loot table, but I haven't yet seen any legitimate source saying that. It's no more rare than any other exotic. You have just as much chance of rolling a Gjallarhorn as you do a No Land Beyond, or anything else. Anyone who says otherwise is merely speculating (so far that I've seen). I see people get it all the time. Keep playing, and RNGesus will inevitably bless you if Xur doesn't sell it first.