He's fading because he risks losing the conditional love of his friends and family in this evil religion. You have escaped that type of love by leaving. But it sounds like you haven't totally escaped that type of thinking, reasoning, or love. By showing your friend what true unconditional love is, you can show him/her that whats outside is not so scary and that maybe there is some hope.
I personally could not have faded, have no interest in fading and for strong personal reasons. Perhaps you are the same. So its more difficult to forgive someone, when in (I'm speculating) our minds they are being deceitful by playing both sides and then top it off by this type of action.
The irony can't be lost on you that we adults have to still be capable of playing these games due to a bunch of senile old men in Brooklyn and some local elders playing god.
I say call your friend, forgive them. Be the bigger person.
Sherry