I will only tell them to buy Bitcoin only based on the money they have and can afford to lose, and I don't think it is necessary to tell them about the units or fractions of bitcoin they can have because it will definitely be very confusing and those who want to invest in Bitcoin are not required to know this forum. I will only tell you that Bitcoin can be an alternative to savings and must take good care of it if he is able to store it in a hardware wallet which also requires money to buy it.