撻Q猛男

What  exactly is he believing in?Christianity has catholics, protestant. There are also other kinds such as the Mormons and Jehovah Witnesses, we can better help you if you can tell us what it is.

Don't argue or force him to agree with you, this most certainly won't work. Try this site for some helpful information:
http://www.freedomofmind.com/resourcecenter/faq/

If it's christianity, ask him to reconsider his belief. Here are some info. to challenge the belief:
http://www.xys.org/pages/christianity.html