The tragic case of Charlie Gard.
A source I read said the guy had his ability to own firearms revoked (or some such language) which I take to mean he would not have been able to pass a background check. It also appears the father was present when the weapons were seized (apparently he was living at his father's home) so presumably the father would have been aware of that fact.
So, yeah, if he isn't charged as an accessory at least expect a civil suit. He deserves some misery.