Controlling an iPhone from another

Is there a way on which I can control an old iPhone that’s permanently plugged to stereo from another one?

I own a Philips ORD7300 that has a 30 pin Dock, and i can’t use a Bluetooth receiver (I don’t know why, it just doesn’t works), so I was thinking on purchase a 2nd hand iPhone 4s, that has Apple Music support, and plug it permanently, so I want to know if is there a way to control it from my iPhone XR o other devices on my house.

Thanks