I know what you are going through Jack was the same way I would cry and want to give up. I bought all kinds of good food for him and FINALLy I gave him cod-liver oil it puts weight on them its called "Nordic Naturals Artic Cod Liver oil with Omega 3-supplements. Its for skin and hair but its 45-calories. Well it has made a difference he only eats "chicken soup for the soul" kibbles and I boil vegtables, and give him treats during t he day. He gets 1-mg a day mind you he runs when I get it out but oh well.
Its flavored peach.
HOpe this helps
Cheryl/ I feel for you