Evidently passing away under anesthesia is all too common for tortoises. But sometimes it's just a risk you have to take. I'm so sorry Olive didn't make it. Did the vet fill you in on what the blockage was and how to prevent it, etc. Hopefully it was a learning experience.
Oh I am so sorry to hear about Olive. What a devastating time this must be for you. I too am Wondering what the blockage was and perhaps more people can learn from this experience as well to help prevent another tortoise having the same problem.
I am so sorry you lost olive this way. But just know you did all you could and don't blame yourself. He was in your lives for a reason and you all loved him so much and I know he loved you as well. Big hugs to you all. Sending peaceful healing felling your way.
I just lost my 14 year old Chocolate lab last week and I am devastated. Only pet owners understand that these are more than just dogs and tortoises. I am very sorry for your loss.