So when they arrived, I took him off the collar away from his protect zone so he could see them up close and wouldn't be barking at the "unknown" intruders the whole time. I then instructed everyone to head down the hill, and not come up to the house, put him back on collar at house and changed clothes.
After some time my elderly mom and best friend awoke from their nap and had come out to walk her friend;s two little dogs. I guess they came back out to visit, at which point my best friends wife apparently asked to take their youngest little girl to the bathroom.
Here's where it gets ugly... in heading to the house, my mom's best friend is chatting with the wife's oldest daughter (of my best friend, I'm single), and the wife is just in front and to the left, also conversing. From the description I got from my mom's best friend, it sounds like in this moment, the youngest daughter of the wife is ahead of the group by 3-5 yds, goes to pet the german shepard (who is now in his defend territory). He thinks for a second, then decides this is a hostile act by this strange child, barely nips her chin, but she raises her arm (naturally defend reaction) and he takes a chunk out at the crook of the elbow.
Hospital report -- its only "meat" bite, she has full articulation of the hand. Required 4 LARGE stitches to allow for drainage.
Now again this is my best friend's family, I love them all dearly (wife included)..... but for the life of me I cannot understand how the mother could be so negligent in letting her daughter get ahead of her in that situation. In assessing the situation, I would place 80-90% of the blame on her (negligence), and split the remainder equally between myself and my best friend (who knows the dog well enough from previous encounters that he defends his zone) for not hammering home NOT TO GO NEAR THE DOG near the house unless I'm between them. He should have done some immediately after I took the dog.
The wife and kids weren't even supposed to be around that long, there were only gonna stay for and hour or 2 and then leave my best friend to be driven home later by his brother. so frustrating....
The wait for the hospital report from the parents was gutwrenching for me as well, had visions of some long reconstructive surgery for bicep/tendons in forearm.
Obviously my dog is now in mandatory quarantine for 10 days, and will have to pay boarding fees.
Here's where I'm looking for input. My mom seems to think we are at fault as far as any insurance is concerned regardless of the circumstances (because it's our dog), and that as a result our insurance premiums will sky rocket. My thoughts are we should possibly pay his deductible, but should we really be moving to pay all costs cash? Our income is basically split between interest from trust fund (fathers insurance) and her social security. Funds are quite tight otherwise, and she will be having to pull out of said trust fund for this.
I guess the thing that gets me the most is this.... how on God's green earth do you ever let your child get close to a large dog (German shepard guard dog no less) without direct approval/supervision from the owner/caretaker is beyond me.


ETA: I consider this closed now and appreciate all input given. I needed to vent my frustrations and have gotten the constructive feedback I was looking for. Thank you all. I have changed the title.