Dog is a completely different dog when left with other dogs

My labradoodle is very well behaved when he’s by himself and alone with us. He doesn’t get into anything, doesn’t bark, and we can leave him at home knowing that he won’t get into anything (we have a pet cam to confirm). From time to time, my wife’s sister stays with us and brings her doodle along with her. The two dogs get a long great with each other, but almost too much. some switch turns on when the two get together and our dog (Winston) acts completely different when they’re together. He’s very obsessed and hyper when the other dog is around. The other dog is a barker and so Winston barks when they’re together. When we leave, Winston gets into something or tears something up, every time (again, the pet cam confirms that it’s Winston and not the other dog(s). He even destroyed one of our couch cushions. I’m not sure what is happening or how to train against it since he only acts up when we’re gone and he’s alone with this other dog. How do I train against bad behavior when I’m not around to correct the bad behavio

I should also add that we routinely takehim on walks and to dog parks, so he gets plenty of exercise and socialization.

thanks in advance for any/all advise.