Will my dog ever be able to change?

He is a Jack Russell/Miniature Pincher/Rat Terrier. He is 5 (I think) and he is inbred. His problem is that he always pees in the house even if he already goes outside. He isn't fixed, and he is really vicious. His sister was the same way and my mom had her euthanized. But this isn't at my mom's house. Will he ever be able to change or will we have to euthanize him, too?