Two months before Joe Clark died of colon cancer at age 31, a doctor gently told him it was time to stop treatment.He had suffered through more than a year of chemotherapy that produced painful sores in his mouth, last-ditch major abdominal surgery had left behind excruciating scar tissue and, probably worse, hope had dried up. But the end of treatment had a surprise effect on Clark and his wife.“It was a whole new way of thinking to wrap our minds around,” his widow, Amanda Evans-Clark recalled. No more &ldquo …