Mom's Feeding Tube

My Mom has been diagnosed with gallbladder cancer. They are going to remover 75% of her liver, and other items. In order for them to do the surgery - she has to be healthy and not jaundiced. They have inserted a feeding tube and it goes directly into her lower intestine - however, she is to have 5 - 250mL cans of this stuff and can only get down 1 teaspoon in four hours right now. She is nauseated and has a burning sensation in her stomach area. When the food is going in - her legs start to jump.
Has anyone heard of this? Any solutions?
Thanks in advance!