I do agree somewhat, or at least to the extent that without spirituality the morality concept is weak. Things like compassion and altruism don't necessarily need spirituality to exist, yet offer vague subjective guidelines for morality.
You could try to talk with him to understand the underlying reasons for his will for a life change. It really could be anything. Or if that doesn't work, seek couples counceling for a couple of sessions.
Well that's fucking fantastic