She may need to learn how to swallow and chew. They just do not know how to do it and need to be taught which takes time and patience. It is not an instinct behavior like sucking. Has she been evaluated on how to chew/swallow food? Is that the therapy you refer to? If not, then suggest getting her evaluated, by going to your MD, and start therapy so she can start to eat regular food. Suggest giving her Pediasure or make milkshakes (milk and ice cream blended) as her source of food at meals/snacks instead of milk, if you have not already. Hoped this helped you.
I am not sure what her height is. I think the last time she was seen by her nutritionist she was in the 5 to 10% for her age. And her weight is around 25 pounds. It is hard for her to gain weight when she doesn't eat food.