I just wanted to send you and Barney lots and lots of healing vibes. I hope he does well with the chemo.
x2! I don't have any experience with MCT but I wish for the best outcome for Barney!
As for food, I noticed in another thread that you are feeding TOTW Pacific Stream. If he tolerates food changes well, you could try Orijen 6 Fish or Wellness Core Ocean; both of these are also grain-free and IMO probably even better quality than TOTW (which I am currently feeding as well).
We usually add a spoonful of wet food to my dog's kibble and we recently tried Wellness 95%: http://www.wellnesspetfood.com/dog_well ... lmon.html#
It also comes in chicken, beef, turkey, and lamb. I don't know if Barney has any allergy issues at all but the Wellness 95% canned makes it easy to limit ingredients/protein sources if you have any known food allergy issues.