I also believe I’ve deduced the actual story behind this after some sleuthing.
The lion’s name is Kiara and she lives at a Black Jaguar White Tiger big cat sanctuary in Monterrey, Mexico. Kiara was rescued as a cub and cared for by Adolfo, the gentleman in the video, until she was re-homed at the sanctuary.
The video showed their reunion, and clearly she remembered and was thrilled to see him.