I have similar situation with my twin sister who is a very zealous Witness. What astonishes her is that I never engage her any any religious talk. I once told her "God gave us reason, not religion" which prevents her from engaging me in any religious talk either.
Even God respects this position because He is not bothered about all those religions which misrepresent and dishonor Him. He knows each one varies in his means to find out happiness. Religions make some happy, atheism make some happy, agnosticism make some happy ... and God takes no serious view of anyone of them which actually shows He is merciful.