just because someone was a JW in the past doesn't mean they can't loose all the moral decency they use to have
That assumes they ever had moral decency in the first place. Liars and hypocrites are found everywhere; putting on a good act for outward appearances is their game.
You gave him a second chance, and a third, and then some. He blew them all. If you keep doing the same thing, it will not get better.