No, Travis has not gave a good reason for leaving. He could have talked to his boss and tried to get along with them better. If he still wanted to quit, he could have just said “I want to work elsewhere”.
you could say it was a good reason or a bad reason depending on your interpretation.. if you wanted to say it was a good reason- write that it is important for travis’ mental health that he is in a healthy work environment. Some may argue that he should stay to be loyal... but loyalty is never a good enough reason to stay in a job. Mental health and well-being comes first. I guess travis could improve his reasoning by saying that he left due to mental health reasons if that was the case.