Jimmy Kimmel's son William (who goes by Billy) is almost too cute for words. The tiny tot was born on April 21 with a congenital heart defect and has since undergone two open-heart surgeries, with just one more operation left to go. In May, Jimmy tearfully opened up about Billy's terrifying condition for the first time on air. Now, it appears Billy is doing just fine, and we certainly can't get enough of all of the sweet photos we've seen of the 7-month-old. Seriously, his smile can brighten up any room. Ahead, we've rounded up all of the cutest photos of Billy, who is surely one of the bravest kids the world has ever seen. Get ready for your heart to melt in 3 . . . 2 . . .