Robert was furious and commented using an ungentlemanly expression - he wrote D. Davis that "Mr. Wm. Herndon is making an a$$ of himself in his lectures. I am getting seriously annoyed of his way of doting things."
He tried to stop the publication. Please see post #20 as for his written communication with Herndon on the matter: http://rogerjnorton.com/LincolnDiscussio...l#pid35484
AFAIK nothing is known about his faith. (I guess you are asking about him attending by himself as an adult?)