Not to be rude but why jailbreak when you didn't bother reading brief instructions?
A few fair warnings on the official evasi0n reads:
- Warning! Over The Air updates of iOS 7 are known to create an issue and make the jailbreak fail. Some devices are then stuck on the Apple Boot Logo. Until we fix that, please restore your device to 7.0.x with iTunes first.
- If you get an error on OS X 10.8/10.9 saying that evasi0n can't be opened, control-click (or right-click) the app and on the revealed context menu, choose 'Open.' On the ensuing dialogue box, choose 'Open' as well.
Requirements - A computer, running Windows (XP minimum), Mac OS X (10.7 minimum)
Good job, we've told him numerous times to update his Mac but he doesn't listen.