His exchanges with you show nothing more than the best he has to offer. Sometimes present, sometimes not. It's all about his schedule and his motivations. Most of us reveal much more than we intend to reveal. Our life stories are written all over us. For those who can read. But you don't need to be a psychologist to see what others are trying to hide.
As per ArtFriend's comments, an "intermittent schedule of reinforcement" accounts for a great range of human behaviors. My drinking stopped "working" for me years before I stopped drinking, but every so often it did the trick. All the pain, the suffering and the abiding sense of loss and despair were worth it on some very deep and elusive level because drinking made me "feel good" once in a blue moon. ISFs also account for why people stay in abusive relationships with other people. "He's a very sweet guy when he's not trying to kill me." A person who's starving settling for stale bread crumbs.
This is an extremely difficult dynamic to crack, but it also provides information on how we're doing with our own lives. The less frequently we respond, the more "grounded" we're becoming, and the less likely we are to respond in the future. One could argue that this also explains in part why total abstinence is preferable to moderation for many of us who have problems with alcohol.