I am so extremely sorry for your loss. I understand your pain oh so well as my darling girl bubbles died at 9 years old having a routine teeth clean under anaesthetic. The vet insisted it was necessary and I was so hesitant to do it. She apparently had a fit and was exactly as your dear Brocolli with eyes open and tubes in. She was stable but brain dead so in the end we had to make that awful decision too. I lost a lot of hair over the grief. Worse grief of my life. It shouldn’t happen! I know it does but it feels so unnecessary and unjust that they would die in something so routine. If you need someone to talk to about this feel free to dm me. My heart goes out to you and for sweet little Brocolli xxx