Well, no dragon will ever replace Pumpkin, that is for sure. You will see him again I am quite sure of it. He will always be with you.
Maybe he had a tumor of some sort if she felt something was blocking him, & he was having trouble breathing. However, their breathing becomes erratic when they decline. More tests would need to have been done to determine the cause of death. I am sorry you don't have closure, that makes it harder.
I know it does make it much worse that Im still left confused as to why hes not here anymore. It seems like just the other day he was happily running around everywhere, now i just have his empty tank next to my bed which is devastating to look at, but i would like to get another one. Just not sure how soon? I feel like trying to "replace" him right after is horrible, i cant even think about it thanks again for everyones support.