Switching Positions?

[IHateMgmt]

Have a pretty easy question for you ATCer's. My brother is just moving from an ATC DOD terminal position to the FAA. He wants to get back to MSP, but so far hasn't received an interest from them. If he took a different location, is there any sort of formal or understood rules of how long he has to stay at that location? Also, if he did transfer locations, would he transfer pay rates or have to start over at the bottom again?

Cheers