Well I feel your pain in a way.. I had a chocolate lab once.. And she was a nightmare with digging, chewing everything up & had bad medical problems.. At one time she was on 8 pills a day just to control her medical problems & even pills to calm her.. She was that bad.. Well she passed on about 3 yrs ago.. Then Heck about 1 yr ago a yellow male lab was dumped at my house by some people that got foreclosed on.. Well I took him in & he is much better than the other one was.. He has no medical problems & guards the house good.. He does not chew or nothing.. He just has a digging problem that I can deal with very well.. My point is Labs seems to be so different.. I would say put a fence in between your house & your dads maybe.. Ask the Vet if their is relaxer drug that can be sprayed or by pill for your lab..