Its probably close to 30 years old at this point. Can be a little bit springy. My 25 year old OM-1 was like that until I had it CLA'ed ($100).

The easiest way is to take a gray card and a handheld light meter or another camera and compare the readings. Make sure the gray card fills the frame.

If you are trying to teach him you will need something that works well or he will be really frustrated.