Frankly, that dog wouldn't live long here. First growl or snap, and it would have been a dead dog. Especially after having bitten your dad. Dogs like that can be time-bombs, just waiting to go off when you least expect it. (Not saying they ALL are, but the potential is there)
Under some circumstances, dogs will even be aggressive with people they know well. I can attest to this - I'm an EMT. I had to go to my own mother's house one night with the ambulance. She has a sweet dog that I know well. It stays with me when my folks are gone. That night, I went in first to...