The muscles need 48 hours to recover. More if more damage is done. I know Scotsman posted that, but just restating. He's also right in having said you'll just be flushing the muscles with blood constantly, giving you a pump.
Your buddy probably has naturally bigger arms anyway, or what bigger before he started doing curls every morning.
You don't need to do more than 3x8 for biceps. They're a small muscle group. 2 sets maximum every other day will do you good, if all you want is to target the biceps. Hammer curls and regular curls will fully target your biceps and forearms somewhat. You might want to change things up for fun and try some drag curls and reverse curls though.