If you are in possession of his rifle why don't you just give it to him (through a registered firearms dealer to cover your arse)...problem fixed.
The point is: So long as the ex lives in NY he can't legally transfer that rifle to him. The rifle is not registered, it's too late to register it and no FFL in NY can legally transfer it. The only way for the couple with the rifle to avoid legal jeopardy would be if the ex went to them and took the rifle back. Then when the ex transports to NY, it is the ex that has the legal jeopardy, not the OP and his wife.
Now, don't shoot the messenger - again (Gitem 12 talking to you). I didn't make the law or support it, just letting the OP (and others here) aware of the very restrictive nature of the SAFE Act and trying to keep the OP and his wife out potential legal trouble they probably don't want.
No...the point is that when it is in the hands of a registered firearms dealer the problem no longer exists.
If the ex wishes to take it up with the ruling authority then he may do so at his own leisure.
