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Yes. it would be appropriate to discuss with him and his wife about seeking help. Many religious people converse with God and Jesus, but it typically does not manifest as Jesus standing before them and speaking to them.
This can occur either from certain recreational drugs or from certain underlying mental health disorders, particularly schizophrenia. Less often, such symptoms can be due to a neurologic condition. Whether from drugs, mental illness, or a neurologic condition, it would be appropriate to seek help.
If he or his wife admit to drug use and they think that they can stop the drug use, it is reasonable to make an initial effort to get off the drugs, but many people need help in getting off drugs.
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