I agree with the others in regards to sending him off for training.
When I train dogs I make sure the owners are with me for a couple sessions, and anytime I work on something new with the dog I tell/show the owner what I'm doing and explain why.

I also agree with Aly that they should give crate training a try, maybe coupled with attaching Teddy to Pat when he's out of the crate so that he has no excuse for not watching him.

If worse comes to worse he can always use belly bands on him in the house, which will only be a band-aid to the problem, but will make it livable. I would try crate training first though.

Good luck!