You are taking some sort of a bet when taking a loan to fund buying bitcoins.
If the guys wants to start of slow and build from there, why don't you buy a couple of 10 dollars first and when you have more fiat use that to buy from him?
You don't have to buy big amounts right away to show your interest in bitcoin imo.
Totally agree with you, if wanted to start the bitcoin buying and selling trading you can start with what ever amount of fiat currency you are holding , so when you see the trading way and earning profit you will gain experience and you will be having more money,
other thinkg is as per i know no other bank gives loan on Bitcoins.