One more website that I find helpful is this one:
http://www.siari.co.uk/
There are lots of reasons why people do it. Maybe you could ask him to look at these websites with you and tell you what feels right to him? The secret shame site has a good list of some of the reasons as well as information for loved ones.
Let us know what else we can do to help you.
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“We should always pray for help, but we should always listen for inspiration and impression to proceed in ways different from those we may have thought of.”
– John H. Groberg