Does anti-psychotic medication help with the disorder itself or does it calm the person down and hide the symptoms and behavior?

Medication alone doesn't help in controlling the disorder. Medication and taking psychotherapy sessions will help in controlling the disorder. Anti-psychotic medication calms the person down.

This antipsychotic definitely help with that disorder but the ones that are sedating can also alleviate anxiety and insomnia.  No they do not hide the symptoms and behavior

It does all three - antipsychotic medication treats the disorder and also calls the person, but the primary role is to treat.