Emergency brake

I agree with Doc and VDC completely.

My suggestion? When your son-in-law is with you AND you park on level ground (note the AND), dispense with the parking brake. The rest of the time, use it if you’d like.

The level ground emphasis is because routinely not using your parking brake on hills can create excess wear on the parking pawl and you may someday find yourself unable to take the car out of park.