Okay. Bear with me. Dreams occur before the REM cycle, which is when you're in "deep sleep". Before, and sometimes after that, your brain is "conscious" and still thinking. What your brain does during dreams is pull things in from your day. Maybe somebody you met, or something that happened at school or work. It mashes together all your thoughts and actions and reminders to create a fantastic vision, a dream, and also why your dream felt so real. So no, it's not possible.
Communication through dreams is not possible. However, research has shown that identical twins can communicate through dreams because they are linked. Moreover, you can communicate through dreams when you start talking when you are dreaming.