You can only catch it from actual v or d. It is not airborne. As long as you have good hand hygiene and the sick areas are thoroughly cleaned after he is ill, you should be fine. I understand your concerns and I would be scared in the same situation. Your dad is a grown man and probably mainly cares for himself and most likely won't leave messes for you. I know it's hard, but go home and get some sleep. You can do this.