Phil,
Maybe they are not really friends.  The question is rather, were you their
real friend?  In the cse of this minister friend, I think you were really
his friend.  He might have been a more evident friend but he was wrong and
probably ashamed of it.  Did you help him with the letter?  You must have!
He went back to the ministry of that little church.  You don't really know
how much effect that letter might have had on his life and decisions.  The
Lord works even in unfriendly situations. Remember the lady who broke the
alabaster box  over Jesus to annoint him for burrial?  Jesus said of her,
"leave her alone, she has done what she could".  You did what you could,
Phil, and the good of that was not hindered by what your friend did.

Ned