According to the article SETI is not doing number crunching on mobile devices, instead users scroll through images of radio signals and click if they think they see a pattern in the noise.
This is using mobile devices to what they are good at, i.e. something point-and-clicky with graphics that doesn't take too much floating point resources and doesn't run unless the user is interacting with it.
It doesn't really apply to a discussion on porting the FAH client to mobile. But I think this quote from the article is a key point:
Getting individuals involved is key to the project, not just to process data, but to get people emotionally and intellectually invested in the mission and lend a new perspective on the world around us, Tarter said.
Which I take to mean that whether or not the SETI mobile app returns significant amounts of data, they still consider it useful for the marketing potential - if you can get people hooked on looking for aliens, they may sign up with their more powerful computers as well.
Candidates for FAH-related mobile applications could be FAH monitoring and/or protein visualization, or a program that lets users fold proteins "by hand".
a) such an app would do something different from FAH client number crunching, and
b) SETI didn't spend resources on this mobile app, it was made by a volunteer who managed to get funding from Adobe.