That's the stupid idea,if you make that you will regret for sure,Bitcoin is not only the option to get additional income.Try to look out other alternative or consult a business counselor to guide you into business opportunity.Selling your things that really important to you like your house and car to get some bitcoin is not necessary.you will have many option out there.
There is only a one way for him to find out will he regret or not. Do not forget,
later he can regret cause he did not do that. Every story have a two sides!
Maybe he live alone, maybe he have other house, maybe he plan to live on
some other place while he wait his investment to bring profit. What ever it is
he probably think that he can take the risks.
We all have options, but to pick the most riskiest you need to be brave. Not
everyone is capable to do that, I am not, but I saw people who risk a lot and
win a lot. Let him to decide for him self, and support any decisions he made!