You would have to let the air out, break the bead and unscrew the sensors from the valve stem. Just held on by a small screw.
As far as leaving them on for your friend, what year is his truck. If 07 or 08, the sensors will not work for him, and if 04-06, he does not need them. TPMS was not started on the F150 until 07. Also if you leave them on the old truck, sensors will run you around $150 for a set of 4.