First what a cute boy he is! Perhaps you could keep him in the container and he could pee all he wants there.......Just kidding!
My boy had been perfectly trained to go outside, but after he had spent a day in a cage free day camp ( where he did tend to pee on the floor there as there were other dogs/smells), he suddenly peed once on the hardwood floor next to a sofa. Aaaaargh!
First time he had ever done that.
So I watched him like a hawk and kept taking him out and he has not peed on the floor since. Aaaah!
So perhaps your dog his reacting to the cat vomit as it is different. Or he was spooked by the different home care situation while you were gone?
So I feel it is tied to some experience he had and just kept doing it.
So for a while you could tether him to you and not let him out of your sight, and also keep him away from the cat stuff until he unlearns the new habit!
Good luck, and please let us know what worked for you.
