He is a spy and should stay in prison.
He is not a spy. Spies are citizens from one country sent to “spy” on another. He is a traitor which means as stated above, it is none of Israel’s business how the US deals with him. However if you look at this man’s life and the details of his crime, he appears to be a bit of a fool who was taken advantage of by Israeli spies. He honestly does not appear to be very bright. For this reason, even though he is guilty as hell, in the Christian spirit (some irony here perhaps), I feel strongly that the man should be let go and rejoin his family in his remaining years.