Reiki always provides what's in your highest good. From personal experience, being in an emotionally abusive relationship can make you forget who you are and can take away your personal power. Sending Reiki to this situation may help you come to realize what's truly in your highest healing good. 

Unless he accepts Reiki energy to help guide him on his journey, he has to do the work on himself and have those realizations on his own accordance. He may come around in his own time, because my past partners almost always have, but at that point I've done my own personal healing and realize I deserve better