1996 Honda Civic Ignition Switch?

Electrical problem
1996 Honda Civic 4 cyl Automatic

My sons car is still not starting all the time. I've replaced the battery, starter, alternature, spark plugs, spark plug wires and cleaned up the ground wire from the battery. I'm wondering if the problem could be the ignition switch. The switch is very loose and if I'm patient enough it will eventually start. The battery is holding steady at 12.60 when I test it with a volt meter. I believe it should be between 13 and 15. This tells me that the battery is not charging. Friend of mine said there could be a break somewhere and suspected the ignition switch or switch wire/s. He's a mechanic and wants to buy the car. I don't want to let it go because I know he knows whats wrong with it, but doesn't want to say because he wants the car for $600. I refuse to let it go because over all, it's a good engine. Sounds and runs great when it's running and I'm determined to fix this problem on my own while I teach my son about cars. I just need a little guidence. Thanks