trackpad select is disabled on my sons MacBook air

computer track pad "stopped" working MacBook air.

The pointer moves around the screen, pinch to zoom in and out works and I've been able to get the screens to switch by randomly using keyboard keys somehow but I can not select anything with the pointer and touch pad. Single taps double triple taps make no selection of item the pointer is on. His finger print ID key works when I ask him to turn it on.

I feel like this is a settings issue possibly or there is a work around to get it to act this way. I am an IPhone user but don't know much about the MacBook Air.

Any help or ways to fix this. Again the touch pad is working perfectly moving the pointer and zooming in and out it will not select when you tap. I've tried tapping many different ways and speeds.