Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
I may be able to help you set this up. I have a few questions first.
Your macbook air.. How is it currently connected to the internet?
Heres the issue. The macbook cannot receive internet using its wireless connection and then at the same time transmit its own wifi hotspot. It only has one wireless card and it can only be a part of one network at a time.
The only way he could create a hotspot with his macbook air, is if the macbook air was connected to the internet via an ethernet cable ( he'd need this adapter http://amzn.to/1QAUc73 )
He would have to connect his macbook to the internet using an ethernet cable..
And then, he could use his wifi adapter to create a hotspot the phone could connect to. And this is how you would create the hotspot.
If you have further questions, let me know.
I strive to provide great service, and greatly appreciate a rating of excellent ( 5 stars ) selected and submitted below this answer or at the top right of the screen. I always answer follow up questions.Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.