Sofia Richie’s tropical proposal may have been straight out of a romance novel, but fiancé Elliot Grainge struggled to ask his future father-in-law for her hand in marriage. Lionel Richie told Access Hollywood Tuesday that Grainge, son of Universal Music Group CEO Lucian Grainge, “was a nervous wreck” at the time. “Poor guy. I thought he was gonna pass out. But he survived it,” the “American Idol” judge and “Hello” singer, told the outlet. “I was gonna rib him a little bit, but I didn’t wanna play. He was gonna faint. So, it was wonderful.” Though the 23-year-old model and Grainge, 27, are you…