you can make a gruel put it in a syringe minus the needle and very gnetly and a tiny dab at a time put it right inside his mouth. also the Nutri Drench can be done this way. Sorry to hear about Wasabi
I don't know about this tumor and I am so sorry your dealing with this it has to be heart breaking, I have been watching and reading just didn't know what to tell you and hoping they would start eating. Do you have any Poultry Nutri Drench? it can be given directly in their mouth. and may help...