Using cryptocurrency for loan its not good ideas, how ever bitcoin and altcoin have speculative price where some time could be on higher but some time could be lower, will be not profitable if you trying make cryptocurrency as lending business.
Because of that, lender require collateral amount more than loan amount. Whenever the price down to the certain number, lender will automatic selling the collateral at the best price. I see that's the best solution to overcome the lender losses in Crypto. Surely lender have to see that altcoin (collateral) price on the market every day.