Yeah me too, I dont think he has that amount of bitcoin coz most of the bitcoiner that has even 10btc doesnt telling to anyone that they have that amount. But anyway if this is true the requested loan must not be higher or equal to the collateral for you to gain some profit.
Wel yes. Remember a lot of users are not really loaning they want something else. To scam people.
Even if you got collateral they will try to scam you. Therefore i would never enter the loaning business. Even for personals loans.