We don't need to know if OP's friend invested in bitcoin or a scam MLM project, but we shouldn't invest with all our savings either. Even if it is bitcoin, it is no guarantee that his money will not be lost, bitcoin is also risky. OP's reminder is very true no matter where we invest but never invest all your money, it is wrong and not recommended.
Most of these investors are people with very mature and mature minds, so they can certainly manage their own assets very well. And in terms of investing, it is not recommended to be too forced because everyone has necessities of life that must always be taken care of as well, so you need to set aside money for this besides investing in the hope of future profits.
Well, in this case it is very important to make a selection of the funds to be used and that includes for investment because after everything is arranged very well and seeing that there are excess funds to make investments, that's where the decision to invest is made appropriately. Not when you have money to make an investment and the next day you have to endure hunger.