And, she hears it twice a week at meetings, from others when she goes in field service and any time she is on JW.org.
It's gaslighting, really. Not many JWs are happy, but the constant repeat of "we're the happiest people on earth" denies their reality.
It's like the organization is the personification of Narcissist Personality disorder. They are always right, all transgressions are justfied, everyone exists to serve their needs and they'll gaslight you in a minute to make you doubt your feelings or recollections.
I'm so sorry you have to watch your mother fall for this and suffer in her old age.