Our family dog is a very cheerful border collie. She's great with people, kids too, but not with other dogs. She is scared of them. We got her when she was a year old and she never learned to walk on a leash. She is currently 4 years old. I've slowly been training her to walk on a leash, but she's very stubborn and difficult when on the leash and a lot easier to handle when she can run around freely. We live quite rural and she generally ignores other dogs, so it hasn't been a problem so far.
While the dog is technically my father's dog, I have been training her mainly since he does not. Every morning he takes her for a short walk, off the leash. I was in the yard and I could hear but not see what happened. I heard my father screaming "come here", followed by two dogs, one quite obviously ours, fighting and my father continuing to scream at our dog.
I then opened the gate and found our dog sitting outside it, clearly scared. I took her in the yard and my father followed after speaking with the other dog's owner. The dog acted submissive and scared. My father proceeded to scream at her for not listening. She tried to flee to me, but he pulled her back and hit her. Not very hard, but she seemed hurt. My father now wants everyone to walk the dog on the leash only since "she can't listen".
I disagree with his behaviour and also with his premise. I'm no behaviour expert, but I am fairly certain dogs are no different than humans. She reacted out of fear and my father made her fear worse. I think she needed to be calmed down instead. He left for work a few hours ago, but she is still scared. I have sent my boyfriend to calm her down while I'm at work, but I'm very worried about her mental state and father possibly making her fears worse.
Since our dog cannot explain herself in anything but body language, how can I help my father understand how her emotions work and that treating her badly is not okay? Note that my father has Asperger's.
An answer explaining how I can tell him why what he is doing is bad is great, but one explaining how I can actually help him understand what the dog needs is even better.