So sorry, it's never easy but especially hard when they are young. Take heart from the fact that you went above and beyond to sort him, but some things just aren't meant to be.
I'm so sorry. If there is anything that can be done to help you through this terrible shock, please just ask. He was lucky to have you taking care of him.
I want to thank all of you for your kind thoughts and words. Your response has been a real comfort in a very sad time. I now have an explanation for Quigley's death. When he first showed clinical signs of sinusitis, a thick, constant but benign discharge of pus from the nostril, my son swabbed him and he was positive for streptococcus Zooepidemicus. The cultures taken just prior to his death are positive for the above and Pseudomonas which is a particularly nasty bacterium found in water. We were flushing him via the surgical site in his forehead with 30mls table salt in 4 litres of cooled boiled water or tap water and that is how we introduced the Pseudomonas. If we had used irradiated sterile water it might not have occurred but it would have cost thousands and thousands and you would still be pumping it in via a non-sterile surgical site which would have been nonsensical. The Pseudomonas had eroded the bone between his sinus and cranium and that final flush infiltrated his brain and caused increased cerebral spinal fluid pressure and killed him instantaneously. Dan said it is like having your neck snapped. Without flushing the Pseudomonas would likely have caused meningitis in his spine which would have been horrific. So, nobody did anything wrong and nobody could do anything differently if another horse presented with the same disease tomorrow. It was just rotten luck that shouldn't have happened to such a sweet horse that showed such grace and equanimity to the end. Please give your horse a kiss on that sweet spot on their muzzle, breathe in their lovely smell and send a thought to Quigley. XXX
Thank you for the update, I imagine it would have been very hard to write.
There was nothing anyone could have done differently, you gave him the only chance that you could and sadly it didn't work out. It is awful when you lose a young horse and you had the added shock of his being a sudden death but at least now you know that he didn't suffer at all at the end, I hope that is a comfort to you at this very sad time.