Millie

Millie is the grandmother of Cecille Horton and the great grandmother of Joanie. Whenever joining her family for Christmas, she would make her special batch of eggnog. On Christmas 2016, Cecille wanted to challenge Joe West's eggnog from his grandmother to her own. Upon comparing the two drinks, both Cecille and Joe coughed fiercely, jokingly declaring that their respective grandmothers were alcoholics.

Season 3

 * "The Present" (mentioned)