Kevin and Ruby Franke married in December 2000. In 2023, Ruby and the family’s therapist Jodi Hildebrandt were convicted after pleading guilty to felony child abuse involving two of Ruby and Kevin’s six children — with each sentenced to up to 30 years in prison. After Ruby entered prison, she began sending Kevin letters from the Utah State Correctional Facility where she is serving her sentence, he tells PEOPLE. “The last letter that I received from her from prison was maybe in March or April of last year,” he tells PEOPLE.