I suggest that you always remain familiar with his room and other areas of your home. If you check his room when he is at school, for example, remember that you're looking for indicators of serious problems -- not minor infractions. In other words, no need to bring up small things with him, because it's best if he doesn't feel you are invading his privacy.
Next, I sense that the psychiatrist treating your son doesn't have your full confidence. Finding someone you respect, someone who educates and empowers you, is important, because there will be many times you'll want guidance. Your parenting challenge is more difficult than most, so your efforts, patience, and commitment to learn all you can are an expression of true love for your son.
Thank you for what you're doing.