Source: Indiana Donor Network / Indiana Donor Network MARTINSVILLE, Ind. — For most, Mother’s Day is a celebration of life and family. But for Brandy Heath, the second Sunday in May is a complex tapestry of profound loss and a unique, lifesaving legacy. Two years ago, just two days after Mother’s Day, Heath’s youngest son, Alex Griffith, died by suicide at the age of 24. A talented musician, a devoted father to a five-year-old son, and a young m…