Heartwarming: Serena Williams Promised A Sick Fan That She Would Grunt His Name Every Time She Hits A Tennis Ball

Even before he was old enough to lift a racket, 10-year-old Jonathan Greene fell in love with the game of tennis, idolizing world champion Serena Williams most of all. So when Jonathan was diagnosed with a rare autoimmune disease, his family reached out to the tennis superstar in hopes of arranging a phone call to…