He can try to fade away quietly without revealing any violations of Watchtower rules to any JW relatives. It is possible that he may fail to fade away because of a number of things- family spying and turning him in, zealous elders seeking to get rid of him, participation in holidays or elections or whatever.
But he may be successful and keep family from shunning him. Whether he succeeds or fails, he will still be out of that cult and free. Or he may choose not to try to hide things. He's still free.
You just never know. I successfully faded and maintain JW family contact, but my JW family is minimal where most are not JW. I am already married and have no kids, so I don't really have to hide things.
Regardless, he will be free of the cult. If he loses family to shunning, he will need others like yourself involved in his life.