You should simply pick one platform and get it right first. Iterate or pivot then once you gain traction, port.

Why iOS first? Does it matter? It's his call.

iOS users are Apple consumers. Among that group there are far more people who: a) are interested in associating themselves with tech-fashion trends and companies, b) have the disposable income to spend (either directly or indirectly via advertising-driven sales), and c) have shown that they are willing to part with said income fairly readily.

I don't particularly care for Apple's products. I find them to be at best of equivalent quality to other items on the market and the aesthetic doesn't particularly appeal to me. But I recognize the value in targeting and marketing to that audience first.

iOS users spend more, are worth many times Android users to ad buyers, get laid more, and are an all around better demographic. It's true - look it up.

http://www.wired.com/2010/08/gadget-sex/

http://fortune.com/2014/06/27/apples-users-spend-4x-as-much-...

http://www.forbes.com/sites/tonybradley/2013/11/15/android-d...

Developing for iOS is less expensive.