The Shepard family discovered when son Maddox was 2 that he had leukemia Maddox’s mom, Geri, was diagnosed with breast cancer two years later St. Baldrick’s, a nonprofit dedicated to raising awareness for childhood cancer, helped them connect with other families (CNN)In June 2009, Brad and Geri Shepard took their two young children to visit their grandparents, expecting a nice vacation and quality time for the whole family. But Grandma Shepard was worried as soon…