Your friend has the ability to schedule updates for a time when he wants. If he doesn’t do that it’ll update when it wants to. It’s in the settings system.The same guy I know who owns a Tesla S was out with his wife at a movie theater the other day and when they came out, the car was updating its software and wouldn't let them drive...he said it took 35 minutes before they could drive home....there is a daily scheduled software update and he said it is usually after midnight but this was an unexpected one...
When he called Tesla to ask if this could happen while driving, they didn't know at that time....they called him back an hour later and said the car would realize it was driving and schedule the software update when it was shut down unless it was an emergency update and then the car would go into limp mode so he could get to a safe place to stop...
Yikes...!