Someone who has struggled with depression or other mental health issues, including signs of self-harm suddenly seeming better and calmer.
It doesn't necessarily mean that person is actually feeling or doing better or healthier than they were. Sometimes it is simply a mechanism they use to put their loved ones at ease so they can proceed with their suicidal plans with less scrutiny. I experienced this first hand with my brother and a some friends. And I heard the sentiment echoed over and over in Suicide survivor groups.