Saving Nick from himself - his own conviction that there are demons and that he is indeed possessed. Since Lacroix didn't believe in possession, he surely thought that Nick was imagining it, so he told him what he needed to hear to convince himself that he is capable of overcoming this evil spirit. Lacroix would tell him everything he needed to hear.

While I absolutely agree that Lacroix did not believe Nick was possessed when Nick claimed to be at the Raven, I think he had some doubts that it could be true after Nick morphed on the table at Vanderwals. At any rate, I think he was not willing to take a chance on losing Nick if it could possibly be true. I do love that scene.

BTW, does anyone else think that Vanderwal initially thought that they were a couple and that LaCroix had led Nick into that "lifestyle" creating the turmoil and allowing the devil into Nick? I absolutely read the scene that way.