I successfully reassembled my buddy's brake thanks to guidance above. Thanks everyone for the help. Only issue now is that the rotor isn't true so he gets some slight rubbing once every rotation. Since he has had the bike for 12 years, not 5 yeras as I had thought, and was riding a front brake that was basically metal on metal for who knows how long (how he kept stopping I have no idea) I recommended that he get a new rotor.