Along the lines of what Ken said.
I was taught to test the flight controls after taxying out, while sitting at the end of the runway.
I lost control of my right aileron the other day, no response at all but worked fine on the ground. I landed with rudder control. Never did figure out what happened and I have flown several more flights since with no issues. (could radio interference effect only the ailerons? )
Sorry to hear about your friends plane. Is it rebuildable?