A few minutes ago I got a call from my neighbor, Jeannie. She's in her mid 60's with a prosthetic hip and uses one of those bad-ass scooters to walk her little pissed off terrier.
Anyways, Jeannie called and said that she'd fallen and couldn't get up. I hustled right over and helped her up, then visited for a minute.
My point is this: If you have an elderly neighbor, get on friendly terms with them, make that offer to help in an emergency and give them a number where you can be reached day or night. It's a very minor inconvenience to you but it may be a lifesaver for them.
And you have to make the offer. Don't expect them to ask you.