ARTIST, Vincent Valdez, whom I wrote about a couple of years ago for the Times, has been working on a series of paintings about war. This recently completed portrait is now accompanied by a tragic story. The young man, Valdez’s closest childhood friend, and a medic who had been diagnosed with PTSD, just took his life upon learning that he would be redeployed to Afghanistan. Too many stories like this. And young John’s story flickers in those haunted, terrified eyes.