Always - Have you thought about contacting the bishop (isn't that what they are in the LDS church?) and saying:
"Look, I'm concerned about my X. I understand that he is joining your church, and that as part of the process he has told lies about me and our R. My concern is not over the lies, but the mental illness that I believe underlies his statements. Please, I would appreciate it if you could be aware that he is not well and watch out for his well-being."
