OP's story is pretty brief so it's hard to tell if it's a true story or not. But you can't blame the OP for not giving any warning to his friend about the risks of bitcoin investing. How can OP give advice when his friend secretly sells property for investment and when he has lost everything he comes to OP? Because not only OP but anyone in this situation will stop your friend if they know they are intending to sell assets to invest in bitcoin. Especially those without any knowledge.
He probably sells it off in a secret way or somewhat, like you haven't thought that your friend will kind of sell it off, but mostly in this kind of situation, for sure, he talks to him about the risk, but again, in those kinds of situations, mostly the conversation is all about profit, like how do they spend it or something, and they are sure they can gain a huge profit without thinking about losing all the money. We are also not sure if this story is true because once you've put out some huge money, you'll research as much as possible to not lose all your money.
do make out some purchase of coins then it would really be that never completely goes to zero or would be having that huge loss. Dealing up with Bitcoin or generally in crypto does involved risks on which there's
no assurance that you would be able to make money without having to embrace out those risks but of course if you do caught yourself that in a peak price because the time that you do able to buy
which the price do make out some opposite direction then you could be always having the option to hold instead for long term and would really be waiting up for that recovery which its most likely the case on
where people would be doing.
In general, then it is really just that right that we should really be thinking up sensibly and be wise when it comes to investing decisions which it isnt only limited on Bitcoin or crypto
but also in other ventures as well. We are talking about money that we do used as capital on here and we should do our best on trying out to survive or sustain.