Hi ScaredyKat. As a retired civil controller and the husband of an ex-WRAF I would earnestly advise him NOT to do it. Why on earth does he want to with a young wife and child? He could be away from you for ages in some dreadful part of the world. OK, he might end up at a UK unit but it's a hell of a risk.
If he wants to get into ATC why not go civil and try for NATS? OK, he might still be posted away from home, but if he was successful at least he'd be in the same country and within easy reach.. and you would soon be able to join him. He would also earn more money, have better conditions of service and enjoy a better standard of living.