Ask the PLO about his father. King Hussein had a playboy rep but an iron heart and soul. It appears his son is made from the same iron. If his army is still dominated by bedouin loyal to their king, the descendant of The Prophet,and if Japan supplies the money for the bullets and gas, ISIS will have many very very bad days. I would expect he will receive covert assistance from Bibi as well.
I doubt it will be covert if ISIS moves on the Jordanian border. I'd expect to see Israeli air strikes on ISIS columns. Jordan has 400 miles of border with Syria and Iraq, and I believe most of those border areas in Syria and Iraq are controlled by ISIS. I would expect Israel to be monitoring the situation like a hawk.