Hello and thank you for your post. I am a master certified GM tech and can help you to resolve your issue.
Some M recievers have FM modulation as an option for working with your stereo. That would broadcast the signal to a specific station and you would tune the stereo to that station to hear it through your stereo.
If that is not the case then you can buy an FM modulator
The XMFM1 FM modulator lets you send the signal from your plug-and-play satellite radio directly to your vehicle's stereo. The direct connection eliminates the static and interference that can occur when using a wireless FM transmitter. You won't have to find an unused station or switch between stations when traveling to different areas. Just tune to your favorite XM channel, and enjoy excellent sound quality.
Installation of the XMFM1 requires removal of your factory or aftermarket stereo. Then simply plug your factory radio antenna into the adapter and plug the adapter into the antenna plug on the rear of your stereo.
these are inexpensive and can be bought here or anywhere else that sells car audio equipment online.
Hope this helps.
Enjoy the gift!