As the OCF resident contrarian, my advice is somewhat different.
I refused a feeding tube the first time I had oral cancer and like your husband found it very tough at the end. I had not found OCF at the time or else I would have panicked since my doctors all agreed that only 2000 calories a day would get me through and I could barely make that. David and Christine are right about another 500 or 1000 calories on top of that is much much better but I thought you would like to know that at 5'11 and a full sized male, I did fine with 2000 calories. I just could not force down another sip of Ensure Plus if I had wanted to and I'm glad I did not know it was technically "not enough" calories.
As far as Ensure Plus, I would take a sip, swallow, then gag and spit out mucous. Take a sip, swallow, gag, spit, It took about a half hour a can but I was bound and determined to avoid dehydration and malnutrition. It worked as I never had to go to the hospital for an IV or treatment, not even once.
Your husband is way ahead of the game if he can actually swallow real food like oatmeal. I lived on Ensure Plus (more calories than Ensure, less than VHC) the month before TX ended and two weeks after that before I could do oatmeal.
Last but not least, I could not have done it without the Patch.
Keep the Faith
Charm