“What does a psychiatrist do for PTSD?”

First let me say that you are amazing. PTSD is complicated. and there are different types to it. PTS with D means disorder. Make sure you know exactly what type and how it was obtained. Trauma, abuse, accident, military etc... even prescription drugs or chemical exposure. BUT in simple terms they don't have the greats rating but can help with getting you on the right track with drug knowledge for the symptoms

Thank you for your question. PTSD can be resolved through different therapeutic approaches, including Somatic Experiencing (SE), Eye Movement Desensitization and Reprocessing (EMDR), and Cognitive Behavioral Therapy (CBT). Within CBT, Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) are recommended. Medications have also been found to be helpful in relieving symptoms of PTSD, particularly antidepressants with the strongest evidence supporting Selective Serotonin Reuptake Inhibitors (SSRIs).
Some of the most common symptoms of trauma targeted by psychotherapy and harmacological interventions include: reliving the traumatic experience through flashbacks, avoidance of people and places that trigger the trauma, intrusive memories or nightmares, insomnia, anxiety, numbness, loss of interest, and depression.

See this link...
https://www.evolvepsychiatry.com/blog/seeing-a-psychiatrist-to-treat-ptsd/
and
https://www.psychiatry.org/patients-families/ptsd