Heart breaking! Fynn was the victim of abuse and, I literally walked into the situation blind. Sometimes it's what you have to do to help an animal in need, just be as safe as you can and, have some knowedge of what you're doing or CALL for help. I initially thought Fynn was only neglected but, it wasn't the case. He managed to get out the door one day when I first took him in and, not knowing if he was a runner instinct kicked in, I bolted after him and, grabbed his collar. Scariest moment of my life.
Though he didn't bite or snap at me he bared his teeth and, I noticed he peed a little from fright. I figured I could let go show my fear and, god knows what will happen or I can show my intention. I loosened my grip a bit but, didn't let go. I didn't change my stance or pull my face away I stayed loose and, said "What are you crazy? Can't go running out the door like a maniac." I didn't say it sweetly I just said it like I was talking to my neighbor. He got the picture that nothing changed just because I was restraining him. He stood up and, didn't move. We were a few feet from the door so I decided screw it, he's not pulling away and, isn't afraid anymore, no one was around and, we weren't near any streets. I let go and, we just stood there. He wagged his tail and, I just said "okay, lets go inside". He followed me right in and, it's never happened again.
He rarely gets in trouble but, he used to get scared if we raised our voices. The first couple times he peed a little and, would just go totally submissive. Now he will come to our feet do the submissive thing but, the fear is gone. It takes time. I can't say Fynn who is a freaking saint wouldn't have done the same thing in that situation. If the leads were that tight around him, it had to be both frightening and, painful. She saw who had caused both of those thing and, reacted.
It sounds like you guys knew what you were doing. It's great to find that your friend is okay and you are both still trying to help this poor pup. Good luck!