I think Bitcoin may not be able to fully meet its demand. The probability of Bitcoin's failure to meet its demand is high. Because we know that Bitcoin can be as profitable in the long term as it can be in the short term. Bitcoin often continues to decline in value month after month. How will he handle the situation where investment is his only breadwinner? Will he be prepared for the loss then? Will it suit him?

I think you should convince him as much as possible so that he doesn't expect this from Bitcoin. If he is not willing to take the risk then suggest him to invest at his own risk where you will be his advisor only and you will not be responsible for any profit or loss. Because you should not cause harm to someone where there is a definite possibility of harm. Better advice for him would be to invest by fiat in a business that is most capable of meeting his needs.