There are certain risks in investing in any cryptocurrency. When you help non-cryptographers to invest in Bitcoin or other cryptocurrencies, you should tell them the risks. Everyone has the right to know their investment! I think the comprehensive introduction really helps the non-cryptographers!
maybe not a good idea if they are too newbies. you don't want them to go into the labyrinth of cryptocurrencies and then make them submit KYC yet. if they are just willing to hold, just tell them to hold or stake. congrats to OP, you will not be blamed if you just choose the good investment and make them hold.
but the uncle seem to be experienced in the stock market which he knew one could buy and sell. the uncle is the easier person to teach because he knows already what to do.