who is in complete denial about his obsessive behavior 
(ROOT (SBAR (WHNP (WP who)) (S (VP (VBZ is) (PP (IN in) (NP (NP (JJ complete) (NN denial)) (PP (IN about) (NP (PRP$ his) (JJ obsessive) (NN behavior)))))))))
(ROOT (SBAR (WHNP (WP )) (S (VP (VBZ ) (PP (IN ) (NP (NP (JJ ) (NN )) (PP (IN ) (NP (PRP$ ) (JJ ) (NN )))))))))