The only thing I can suggest is to pray for him and to very gently guide him in the truth. Remain steadfast in your own faith; pray and cling to Christ that his errors do not begin to contaminate your own mind. Be careful not to become angry or overly emotional during discussions, since that will call your maturity and the strength of your argument into question. Enlist other people to talk to him and to pray for him. And bide your time.
Prayer does work miracles in such cases. A few years ago my mother, who has been an extremely devoted Catholic all her life, suddenly was charmed by a certain priest in her native country who had amassed a significant following on social media. This priest kept saying Mass even after his Bishop forbade him, and he constantly berated the hierarchy of the Roman Catholic church on youtube video. My mother, and many others like her, were drawn by his apparent commitment to traditional, pre-Vatican II church traditions. I personally tend to be pretty conservative myself in such matters, but I really thought that this reformist priest lost his credibility when he refused to obey his bishop and rebelling, continued to celebrate the sacraments. Padre Pio and other saints like St. Faustina would obey their superiors even if it went against what the Lord Himself told them in their visions.
For a while, I was in despair. My mother’s soul seemed in great peril after so many years of keeping the faith. I did several things. First of all, I refused to listen to the priest’s youtube sermons when my mother put them on and when I noticed that a local chapel was beginning to adopt too many ideas, I refused to attend church there. I believe that my prolonged silent resistance might have done some good, even though my mother never admitted it.
Second, I thankfully had a great-aunt who, as a nun in my mother’s native country, was very well informed of the entire situation. She spoke to my mother repeatedly and prayed for her continually (God Bless her!).
Third, I spoke to mom directly, but these discussions did not do too much good work. She was too fired up by all those passionate sermons to listen to me very closely, but once or twice she did admit that I had made a good point. This was probably the least effective thing that I did. But hey…that’s what you get when you think that you and your words can solve the problem instead of relying on God to help you out.
Fourth, and most importantly, I prayed. Not as much as I perhaps should have, but I did do some praying. After a couple of years (God does not work instantaneously, sometimes!) the miracle occurred. There was a visiting, intelligent exorcist at our parish, and I encouraged my mother to ask him about this particular priest. She went, and he informed her in no uncertain terms that this man had basically started a sect and that despite his claims, the Vatican fully approved of the sanctions imposed upon him. He mentioned that following this priest had reinstated an evil spirit into someone who had previously undergone a successful, Church-approved exorcism.
My mother, thankfully, appeared to lose most of her support for this priest, and to the best of my knowledge no longer listens to his youtube sermons. Praise the Lord!
