First question would be "Will it fit?"
The next would be "Is the control system compatible?"
I recall that ours in internal regulated but still have 3 wires
It really depends on how the PCM in both trucks control
I did look up the 06 and found one wire goes to the battery
a second wire also goes to the battery and the third to the
instrument cluster. Now doing back to charging systems from
school the 1st wire to the battery is the B+(charge power)
the next one to the battery is to operate the regulator and supply
the power for the field coil. The last one is the ground/control
wire for the PCM and indicator.
Short answer is it should work with some modifications to his truck
if Ford did not change too much maybe very little or none. I would have to know
how his charging system works. Maybe one of the Ford techs can give some
input on this.