... For how long should people understand the importance to have bitcoins for emergencies such as this one?
Okay let's assume the lady has bitcoins on her non-custodial wallet but she still needed to sell it for fiat because the hospital doesn't accept BTC. What if she tried to trade it on a centralized exchange and the platform suddenly froze her account for some reason? That's still going to be a problem. How about P2P platforms? A lot of them requires bank accounts for trades so the same issue.
It's not really bitcoin's problem but the point here is that there is always a risk as long as people continue to use centralized platforms.
That is how anything in life that is centralized can do, to freeze your funds or block your account. But using a noncustodial wallet and a decentralized exchange make it not to be possible because you will have the full control of your money. No central authority is involved. I always hate to see people that did not commit crime and have their funds forzen.