Years ago I wrote an article with Rebecca Moore about why these illnesses are not taken seriously. It's still valid and will help you understand what you are up against. Find it on my top page . Treatment of these illnesses is symptomatic, meaning that one tries to make the symptoms better. Sometimes this is very successful, sometimes it is not.
Some kids get better over time.
Others stay the same or get worse. You have to do what you can and hope for the best. Patience is a necessity. These illnesses are stressful. They cause depression and anxiety.