I had one experience with 2 GSDs and my brother. Ever since i was little i would get to a dog before it got to me(my mom always tried to stop me), but with my uncles 2 dogs i was the first to run up to pet them, not asking(bad i know) but they were very friendly to me. when my brother came ripping around the corner and stoped dead in his tracks because he was scared, the dogs started growling at him, sencing his insecurity. Being scared can be a harmful thing to yourself when confronted by a more dominent dog. I personally am more scared to pet small dogs than the most muscular pits or presa canarios. Being a dog groomer i know first hand that the little guys can be more nasty than the big guys. But I really wish i could help with a situation like that. its horrible being that scared or situations(ive got severe stage frieght). i hope the best to your friend