Everything about the birth of Jimmy Kimmel's son Billy was going great, according to the late-night host -- until things got really scary.&nbsp;William John Kimmel, born April 21, had a congenital defect that sent him to open-heart surgery within days of his birth, the new dad shared Monday on "Jimmy Kimmel Live!"&nbsp;Kimmel&nbsp;tried not to get emotional but failed as he talked tearfully about Billy's color not being right and tests being run and more and more doctors and nurses and equipment showing up in the neonatal intensive care unit at Cedars-Sinai Medical Center.&nbsp;The diagnosis, Kimmel said, was tetralogy of Fallot with pulmonary atresia (click that link for an explanation), and surgery was needed. Billy was taken to Children's Hospital of L.A. by ambulance, and on April 24 underwent a three-hour surgery to repair a hole in his heart. It was successful.&nbsp;Six days later they brought Billy home, and dad says the kid's doing great, though he'll face another surgery when he's older. Kimmel showed off before-and-after pictures of the baby, one with lots of tubes and gear and the other with simply a big, goofy smile. &nbsp;"Poor kid, not only did he get a bad heart, he got my face," said Kimmel, who'd taken a week-plus off work because of his family emergency.&nbsp;Kimmel had abundant thanks for the medical professionals, friends, co-workers and family who'd offered support. "We had atheists praying for us," he said, and even sworn enemy Matt Damon sent flowers.&nbsp;In closing his 13-minute opening monologue, he made an&nbsp;emotional, passionate plea to politicians who would be considering healthcare legislation and health funding in general.&nbsp;"No parent should ever have to decide whether they can afford to save their child's life," Kimmel said, fighting back tears as he talked about other families he saw at Children's Hospital. "It just shouldn't happen. Not here."&nbsp;Updated, 8:32&nbsp;a.m. May 2: This article was updated to add additional details.&nbsp;This article was originally published at 11:57 p.m. May 1.