When this technology is adopted in all countries, the old people you are talking about will no longer be alive. And you will be in the old man's place by that time. So there will be no problems, since you will keep your knowledge about bitcoins and will help those who do not have them.
LOL great analysis. I am afraid there will be other technology that OP as an old person won't understand at that time, so OP's grandson will post on social media about how to make old people understand about the tech!
Old people adopting bitcoin seems somewhat risky I think they should rather stick to using fiat currencies where issues can easily be addressed and solve.
At some point of life people don't want the change. so it is expected that the old generation doesn't welcome bitcoin as a currency. Because all of their life they chased fiat not some digital money that they can't touch or feel.