Since people are still commenting here on what they don't own, and passing along miss-information which is very dangerous in itself, especially for these types of events, here's what can be done and can't. You CAN use Active Pause to pause the sim - HOWEVER, and this is a BIG HOWEVER, your aircraft will still burn fuel and weather will change and time of day will change. You can also use the ESCAPE key to go to the main menu to pause it, however time of day will still pass and there is no way to go back to where you were earlier.
So yes, your son IS telling the truth in this version, there is no real way to pause the sim.