Not all moms are worth living with... what with putting the dog about a three year old granddaughter.

I think you missed this bit "mauling her leg". It wasn't simply a bite, that dog tore into her. Yes dogs can turn on a moments notice. Look how many stories there are about family dogs being left alone in the same room with a baby to have parents come back seconds later because a dog decided to attack. How about the time a dog decided to chase me down the street when I was 16, all because I had the audacity to ride my bicycle past him in the yard, I'm sure I deserved the 10 stitches and rabies shots because a dog "simply does not bite without reason". For an animal rescuer, you must live in a very sheltered part of the country where dogs are 100% innocent 100% of the time. Also caling the victim a brat, shows your true bias

Animals attack people for no good reason all the time. You're probably right that there was a reason. Maybe she moved her hand too fast or maybe she smelled funny or maybe she was sitting in the room close to the dog and the dog didn't like it. I have seen many dogs attack people for no good reason and I have been attacked by dogs for no good reason. Having a reason and a good reason is totally different. Victim blaming does no good here. Dogs attack for all sorts of reasons and probably half of them are unknown to us and the people that the dogs are around.

@Blueraspberrycat - Dogs absolutely can attack unprovoked. It happened to me as a young child, though not nearly as severely as this unfortunate toddler. (I was tackled in a leashed area of a public park. The dog was unleashed and was likely playing, but too aggressively, which shows a lack of training. I was winded and couldn't get up for a few minutes.) You weren't there, you don't know for absolutely sure what happened. If the toddler was acting out of line, the dog would have given warning signs first, such as growling, barking, slapping her away with its paw, light nips, etc. This sounds like an immediate all out attack, according to OP, and OP's mother never trained her animal. Get over your self righteousness.

@Blueraspberrycat When I was 13-14 riding in my Grandpa's car in the back seat with his poorly trained, spoiled Lhasa Apso, I looked over at it briefly, looked back out the window, and the little bastard had bit my arm enough to draw blood. My arms were by my side, and I was looking the other way. I'm sure he felt threatened or cornered in the car, or that I was taking his spot, but it was totally unprovoked in any way. I was just sitting there and had been for over an hour on that road trip. Every single grandkid was bitten by one of his two dogs he had when we were kids. Sometimes dogs are touchy and twitchy and unstable, and can bite you unprovoked because they feel threatened, even though you did nothing wrong, especially when humans are so bad at reading certain dog body language cues, especially little humans.

What the victim blaming BS is this? A poorly trained dog absolutely can attack without what we would see as provocation normally. I have seen it happen, have heard from dog trainers working to correct these issues with poorly trained dogs for years, and have known several people who have been attacked, bitten, or full on mauled with scars and stitches, and the "provocation" was "they had food and didn't respond promptly to the dogs begging" or "they took too long to respond to a demand to play" or even just "my master normally finds it funny when I bite at things, and my owner said the word I normally associate with their approval to do this." Do us a favor and reflect on your words, your life, and your experiences. An apology to the OP here might be appropriate, too.

If you put a dog before a human you got it wrong 200%.

In many places you don't actually have hospital bills or just small ones. This was outside the USA - it may well have been free.