Your post sounds like you are a loving a thoughtful mother and caregiver. Its not easy watching someone you love have problems like this. You must be very strong to not break down in front of your daughter.

For her sore mouth, she should be rinsing several times per day with 16oz warm water, 2 tsp baking soda and 2 tsp salt. If it burns then go down to 1 tsp salt or omit it. There is also something called magic mouthwash. It has several variations. Its a prescription medication, mine was lidocaine, malox and benedryl. She would shake the bottle real good then take about an ounce in her mouth and swish it around for about 20 seconds. It should numb her mouth long enough for her to be able to eat decently. Ask her doc for a prescription. These things will make her life so much easier. Its very difficult to eat when your mouth hurts. She must continue to swallow even if she gets a feeding tube. Her muscles will very quickly 'forget' how to swallow if unused.

Keep up the good work encouraging your daughter. Never give up!