he went and sold his property to invest on Bitcoin without been knowledgeable about it. he went ahead and invest but loss everything because he doesn't know how to trade Bitcoin.
Actually investing in bitcoin never loses or loses if you keep holding it and waiting for the new ATH later. But it can be a loss if your friend doesn't save the seed keyword properly, which if we forget we can't access the bitcoin wallet, apart from that I don't think there is anything to lose when investing in bitcoin.
Yes, everything we want to do requires basic knowledge, because without knowledge everything we do will definitely not run smoothly, including investing in bitcoin. At least we have to know how to store bitcoin properly by using a good wallet and knowing the purpose of bitcoin being created, that way we know the fundamentals of bitcoin. If we all understand this, I don't think there will be any more losses like what your friend experienced.