I think that investing in the mainstream currency will be a very good choice. The prices of Bitcoin and Ethereum are very low, and they are slowly rising. I think this is a good time for investment.
My advice to them is just continue using crypto and learn new things because its better if you have knowledge before you doing it and also because it can help you to understand it and it easily to you to wok with it. Also i want to suggest to them to study or learn the situation of the market to make decisions to do, so they can decide or they can find another way what the best to do when the market is having trouble.