Desktop and iPhone traffic are better converting than Android traffic, so advertisers bid higher to display on these platforms.
For this type of website, he should be bidding desktop - will pay maybe 40% more per click, but much better site engagement.
FB Ads still have a long way before the tools are as robust as Adwords, but learn the platform and run more tests before you trash it. Unless you're going for something ultra-targeted it's rare to nail a CPC platform on the first go.
A way to attribute view through conversions is to have Perfect Audience run a test for you:
Keep cookie-ing people but don't show half of them any ads. Then compare the conversion rate to the people shown ads and come up with VTR attribution coefficient.