If your siruis unit has a headphone jack on it, you could find a stock radio with an aux port and install it into your car. It would have to be programmed to the car by the dealership, but that way you could plug your siruis unit into it aswell as your iphones.
If you want to go with an aftermarket radio, you can buy the metra 99-3303 which allows you to keep the DIC. That one you linked, being sirius ready, means you have to buy another module to use the sirius features built into it. If tou get the iphone cable, then you can plug your iphone into it, allowing it to charge and get the adapter from apple that would turn that plug into the plug your husbands iphone 5 requires.