I understand that you don't want to do nercopsy. I just wonder and wonder why he passed, but I would not do nercopsy, either. When my chins passed, I was going to get nercopsy done and get them crimated until the moment in which I saw their bodies (separate incidents in separate days though).
I just wanted to pet them, hold them, and take them home.
I iced their bodies with frozen bottles (that was summer), and burn candles to cerebrate their lives. I put the bodies where my other chins could see, and let them say good bye to one another for an entire night.
In the next day, when the candles were all burn, I burried their bodies under a tree with their favorite treats in their hands.
Whatever the money that I had ended up saving by not doing nercopsy, I spent on my remaining chins, to keep them safer and healthier, and to spoil them even more and more. The money may worth more to spend on your remaining chins so that they could also live the unlived life of your passed chin. At least, I thought that way, and I remain feeling that it's my preference.
I also understand that other people may say, to run a nercopsy will ensure that you won't make the same mistake again. It's true, and I respect their view. At the same time, I just can't help doubting that vets could tell what might have caused the chins' death for chins' being such small and delicate beings. I feel (although I am just a lay person) that nercopsys on small animals may not be determinative as much as that on human bodies. Also, I feel that vets would avoid making clear announcements as to the causes of deaths because they don't want to be bound by their opinions. So, I might keep wondering why, even after a nercopsy...
Please give my love to your past chinnie, and may he rest in peace.