Dialing through the radio isn't gonna happen, but assuming there's a way to manually switch over to the phone on the headunit somehow, you should be able to use the mic and speakers. If you can figure out the inputs wire it to a TRRS 3.5mm jack like so and plug into your phone.
I don't know how the audio system handled receiving calls, if it automatically muted the stereo and switched over to the phone or whatever.