Hi Shannette,
My husband had BOT cancer as well. He got a feeding tube, but rarely used it. In fact, he used it for any disgusting meds more than anything. He drank the Ensure the entire time, ate scrambled eggs and pasta spirals with tons of butter so they slid down!! He lost 56 pounds during tx. He had it to lose though, but it was a lot of muscle, not only fat. I also made him milkshakes now and then. Your dad can do it without. He seems very determined as was my Kevin. Just be sure to push the water too, and iif he begins to get lethargic or weak or very crabby, he's probably dehydrated. He should be able to get fluids from his mo.
Keep in touch!!
Kathy