Your son-in-law is very misguided and wrong. Using the handbrake does not affect your car’s life or reliability. Having said that, in cold climates you will find many drivers not using thier handbrake since under certain conditions it can freeze up.
If you parked in a moist, warm underground garage, and went and parked out in -40F weather and applied the brake it could easily freeze up. Similarly, if the car is driven through a puddle, and parked ovenight below freezing with the brake on, it could happen as well.
Where I live, all these things can happen, and I use the handbrake most of, but not all the time.