Borrowing money from the bank to invest in crypto is essentially betting on which asset would appreciate more, a currency which suffers from inflation and has unlimited supply or an asset with storing value + utility. So yes, it would be weird not to do it.
If he borrows and invests in a bitcoin and the market is a little dumped for a while, how will he repay his loan? We know the potential of Bitcoin which is a market dump but we don't have much tension. But when someone invests that money by borrowing money and the market suddenly dumps that investor will be under a lot of pressure to repay the loan. So in the case of this type of investment, it is necessary to make money which will not be a big loss even if it is lost.
Investing in crypto is not something easy and the risks are also big so consider again before borrowing money to invest,
use cold money and I think it's the most appropriate thing,
the crypto market is really difficult to predict if we are not careful anytime we can lose money