I am so sad reading what happened to you and Ying.

Diabetes is a VERY difficult disease and you can't feel that you let him down because he passed. You were loving and caring and getting him to the vet and giving him the food and meds and attention he needed. It is a very demanding disease, and it is unfortunately unpredictable at times. I think you did a LOT for this special kitty, and I truly believe that he knows that.

RIP dear Ying.