The Lightners enjoy life as homebodies within their tight-knit family.  How close?  Lisa says, “My only brother married my husband’s only sister.”  Let that sink in for a minute.  These sibling-in-laws band together through good times and bad. It’s the kind of support the Lightners need.  Lisa and Dan have two sons, Brian, age 4, and Kevin, age 6.  Kevin has a rare disorder called Chromosome