If they'll need it, I can make you sure that they will understand it very quickly.
For now, a lot of countries are not exposed to digital transactions and still using fiat money as a mode of transactions, and it is most reliable to use for them since everyone knows it already.
I think someone could easily understand bitcoin when explaining to them or someone teach them how to use it.
It won't be easy because many of them are still behind, what i mean is ,many of then doesn't know modern technology and how to use it. The easiest way i think is to teach them one by one or let their love ones teach them so that they can understand it. Also in teaching them avoid to introduce bitcoin in a complicated way. Just make it simple so that old people can understand.
Some countries that already exposed to digital transactions could easily adapt to cryptocurrency and bitcoin in my opinion. Teaching them or helping them understand how to use or what is bitcoin is going to be easy compared to someone that don't really up to this kind of technology. I guess you need to be good at explaining in order to help them easily understand bitcoin, their are only basic knowledge at points that they just to understand it and use bitcoin as a mode of transaction.
I don't have a readymade answer for this. My father is 78-years old and I have been teaching him how to use a smartphone for the last 4-5 years. And even after all these years, he can only do the most basic tasks on his own. I have given up teaching and I guess he will be OK with whatever knowledge he is having. When it is so difficult for the old people to learn even the basic technology, I don't know how you guys are expecting them to understand complex technology such as cryptocurrency and Blockchain.
I guess we have the same thing, as I teach my father using a smartphone and operate video calls its a bit difficult to help them know how to use it but overtime I can see some improvements.