I have a plane with Hitec gear installed (RCD3800. which is a 7 channel FM, shift select, 72Mhz receiver).

As long as it's on the same channel as my brother's Futaba 7 channel FM transmitter (72Mhz) he should be able to fly the plane with his Futaba??

correct,does this one use a jumper for shift selection?if so it may need to be changed.

I'd have to take a look tomorrow but I do believe there's a jumper on the Hitec.

Thanks