From what I've learned from reading up on trauma, seeing videos, and talking to people who have/who've had PTSD there doesn't seem to be one way to handle recovery? Therapy is the main go to, but some people use exposure therapy (which is exposing yourself to the thing that traumatizes you in a controlled, safe environment). Some find healthy ways to cope, like exercise, meditation, gardening, etc. Things like that. I've also seen people use different methods to "come back" when an episode is triggered, like some keep rubber bands on their wrists and snap them to bring themselves back to reality. Or they use music, talk about what's happening with a friend or family member.
With some people nothing works.
How you depict your character dealing with trauma varies based on their personality, and background.
Edit: Oh! How you depict a character with trauma can also depend on the type of trauma. PTSD from abuse may be handled differently than PTSD from war or seeing a traumatic event.
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I have a character who has PTSD, and for most of the comic I depict them as moody, nervous, manic, paranoid, lethargic, and generally unhappy. Later on when they get help it's a long, difficult process because they have trouble asking for help, and has a lot of issues with self-hate and anxiety. This character is also extremely stubborn, and is very sensitive about spending money. Most of their help comes from therapy, having someone they feel comfortable with, and finding methods to chill out their mania and anxiety. (mostly using yoga, relaxing music, and finding hobbies). The one thing is, even though they do get better, they won't be 100% because all the years of trauma has left mental scaring that won't ever totally heal.
Of course, I'm no expert, this is just stuff I've learned via studying. Take my word with a grain of salt!