Has anyone had a cat develop erosive ulcers on the roof of it's mouth.?

My 3 year old abbysinnian got thin and weak, then I noticed blood coming from his mouth. None of our vets had ever had a cat with this rare problem. It's like an auto-immune disease, my cat had been bleeding for weeks, before I even noticed. Unfortunetly there is no cure, except for constant transfusions. I guess I must be very unlucky. After 6 months of treatments of cortisone, special diets, and being shut inside 24/7 he was still bleeding so I sent him to God.