Change doesn’t come easy for most people. No one jumps in glee when they are wrong. They are even less reluctant to pursue anything that might lead them to possibly being wrong. They’d rather be ignorant and happy, then right and unhappy. Or atleast that’s how they perceive it.
It was a kick in the gut when I first started venturing into the Catholic Church. To think that what I was told wasn’t only wrong, but that in light of the evidence it was pretty obvious the Catholic Church was the Church started by Christ. It hurt, it hurt bad.
People naturally stay away from pain and move toward pleasure. Your mother in law is doing just that.
Unfortantely, people fail to realize that having it right is true happiness.