Rick Case, the South Florida auto dealer entrepreneur who built his business into a $1 billion enterprise, shared his wealth with those less fortunate by underwriting the growth of the Boys & Girls Clubs of Broward County, Habitat for Humanity homes in Pompano Beach, and college educations for scores of at-risk children. Those were among the many causes that Case and his wife, Rita, supported over the years, drawing broad backing from a wide spectrum of donors.