Many of their old friends are no longer with them, but they've found new friends. I have many patients who have no scars, no physical problems, and have largely returned to their own job, yet they're different. Sometimes those people have the greatest difficulty with acceptance. These emotional phases really don't correlate with how physically impaired they are, or whether they return to their own job or not. It varies with the person.
Some people tend to handle the stress of a head injury better than others.
In general, people who do well emotionally tend to have a very strong work ethic. They tend to believe that it's important to contribute to society and to people around them. It's important to help others. They look outside of themselves to see what they can do to make the world around them better. In my experience, these people tend to do better.