Dogs  

I would get a book or video on the people who train dogs, the ones that seem to know what a dog thinks and they seem to be able to control any dogs, they are so good....

i too had a female dog with me....when i was in pano aqil.but when my father get posted from there we gave it to someone else for free....it was a nice dog and of gud race,very active and robust

I would tell the friend they needed to control their dog and if it kills the sheep or attacks you, you will hold him (the friend) responsible. I don't know the laws where you live but here the pet owner is responsible for their animals' actions.

By the sounds of it this dog has had too many "lessons it would not forget" already. Please say you don't mean you were going to "give it a hiding", when you do that, all you are doing is teaching it to hate humans, be afraid, or to be violent.
Sheep dogs work by instinct with some formal training on the side to fine tune skills. All dogs need training when they are young so they no what the limits are.
I live in an area where it's common practice apparently to tease and annoy a puppy who is destined to be a pig or roo killer so that it becomes very annoyed and then aggressive. When they're not hunting they are chained up and lucky if they get fed. Other people around here have dogs, up to six sometimes, who just stay chained up. No exercise, no games and they are fed roadkill. Sometimes.
The sickening fact is that it's a way of life here and people don't think they are doing anything wrong. It literally makes me sick.
I have a reputation for having the best looking, best trained, best taken care of dog in the district. Her glossy black coat shines and her muscles flex and ripple. She doesn't smell and she's very friendly. I think I've shamed a few people but they don't do anything differently as a result, sadly.

Well I think that he needs to get the Dog seen by the Vet to find out why it is reacting that way, also there is an option of Training Classes I have to admit that I would certainly no be happy if my Dog did this and it is not good that the Dog is doing this

Well, i do not believe in any kind of physical abuse, they only do what their instincts tell them is right.
Sheep dogs are different, they need to be doing something all the time (we used to have a couple pf kelpie X's) & they were perfect - mind you i had to spend a good part of every day out the back playing fetch which i didn't mind.
I wonder whether not being your dog, he knew he didn't have to listen to you? My dogs are like that sometimes, they wont listen to anyone other than me since to them, i am the Alpha Male!