LOS ANGELES, July 2 -- The pediatrician went quiet first. That was the detail Nara Smith kept coming back to when she finally told her followers, more than half a year later, what had actually been happening behind the perfectly lit kitchen videos.

"I just remember him going really quiet and calm, and my heart dropped," Smith said in the video posted to her social accounts, describing the moment a doctor examined something she and her husband, model Lucky Blue Smith, had noticed on their 2-year-old daughter, Whimsy Lou, and had assumed was minor enough for a routine pediatric visit. It was not routine. Whimsy was diagnosed with cancer late last year, NBC News reported, and has been undergoing chemotherapy since, a fact her mother chose t...