I have oddly relatable personal experience with this...

I was spending Christmas and New Year with my friends abroad, having the time of my life, when my grandmother died. My family didn't want to tell me and ruin the trip, as they all knew it isn't want my gran would want. I, too, was told as soon as I got home. And honestly, you feel helpless enough without there being hundreds to thousands of miles in between.

And with dogs, my last family dog Bobby, my stupid brilliant Sprollie, became very suddenly sick and I had to choose to put him to sleep on my own. None of the rest of my family were in the country, and I had to make that choice. I made it in Bobby's best interest-- keeping him alive for the sake of my family would have been selfish and cruel, and I would have regretted it for a very, very long time.

NTA. You did what you could for her, no one could have saved her, not even him being with her. Him being devastated in Amsterdam wouldn't have helped anyone. I'm sorry you're going through this.