Sorry to hear about the teeth but, a 9 year old white poodle mix, this is fairly common. The small white dogs in general seem to have genetic predispositions to bad teeth.

Do you remember back in September when my foster dog, Marlin, had 38 extractions? He had quite a few bad days and even had to return to the vet for fluids and another pain injection, he was so unhappy and getting dehydrated. That was 3 days after the surgery. He was on soft foods for about 6 weeks while everything healed up. I started with canned, then moistened dry kibble with warm water and mixed that in, started reducing the amount of canned food. He now eats dry kibble again. Of course, he scouts around to see if there is anything BETTER available first. And every now and then he STILL barks at the dish, to see if I'll break down and give him some of the yummy soft tasty stuff. (I don't do that anymore!)

Point being, she and her mom who watched the dog will just need to be patient, the dog will eventually recover!