Hi OP, someone (a stranger) did this for a close relative of mine and although the outcome was not as happy, it did buy us more time and a better chance.
I am incredibly grateful to that person and mention often what their actions gave us that we wouldn't have had otherwise.
I am fairly sure that we asked for our thanks to be passed on and I think another relative of mine may even have made contact but honestly I was in such a state for an extended period of time that I couldn't tell you which way was up for months (and i wasn't even the one it had happened to), so I couldn't tell you with any certainty what messages were given or got through.
I do remember hearing that the person who gave CPR was enquiring about my relative's welfare once or twice and, despite my heartfelt gratitude, I also remember an extremely unreasonable feeling of wishing to be left alone as I simply couldn't cope with anything else, including basic niceties to this wonderful stranger.
It was very contradictory and completely discombobulating. I think and hope my other relative handled it much better than me and I hope that person knows how grateful I am (now, years later, in a much less fraught and complicated way!)
All of this to say, something similar may be going on here and it doesn't mean that the neighbour isn't it or won't be extremely grateful to you.
It must have been so difficult for you but you did a wonderful thing - well done and thank you!