The home insurance people will absolutely nail him on this. They'll eventually send someone out to inspect the property on a policy renewal. They'll refuse to renew the policy until the code violations are corrected. And they'll definitely notice and have questions about the odd 'shed' that looks new and very out of place.

If he has really wired it as it seems, if anything consequential (unrelated) happens to the property in the meantime they'll use that against him when they inspect post event. They'll try to claim he breached the policy prior to the event.