What about the ignition switch that's on steering column. When you say will not start does it try to start or it's just dead? Mine went out and when it did it would sometimes start then it was dead to the world when you buy the new switch it comes with directions. Maybe have him drive it home and then mess with it just don't turn it off also wait a while others will chime in. Good luck! GMC
PS-It's not the switch where you insert key into it's on the column that has a rod on it like towards the brake/gas pedel on the top part of column but the key moves the rod to start it or tell it power it up to start or turn on radio or shut off.