Hard as it may be to envision a hilarious comedy about a family facing the mother’s descent into dementia, that’s exactly what Colman Domingo has written in his new play at Vineyard Theatre. Dotty Shealy (Marjorie Johnson) is the matriarch of a middle-class black family who have lived in their West Philadelphia row house since 1954. The father, now deceased was a successful physician. Her eldest child Shelly (Sharon Washington), now in her mid-forties, is an attorney and a single mother. Middle child Donnie (Stephen Conrad Moore), now 40, is a gay freelance music critic in New York, where he lives with his activist white husband Adam (Colin Hanlon). Youngest child Averie (Libya V. Pugh) is a brash would-be entertainment whose 15 minutes of YouTube fame has led only to a cashier’s job at Shop Rite. Fidel (Michael Rosen) is a sweet-natured unlicensed health care aide from Kazakhstan who takes care of Dotty three days a week. Jackie (Finnerty Steeves), a white neighbor who was Donnie’s high school sweetheart and who fled to New York when she learned he was gay, has suddenly returned to town and has joined them for their Christmas celebration. There is much hilarity, but the underlying situation of Dot’s deterioration is no joke. During the second act, the play bogs down a bit with some didactic moments and some sentimentality. The ensemble cast work well together. Scenic designer Allen Moyer is a triple threat: he offers a pointillist front curtain depicting the exterior of the family home, a first act kitchen that really looks lived in, and an attractive living room for the second act. Costume designer Kara Harmon has dressed the characters aptly. Director Susan Stroman shows that her talent is not limited to musicals, although she does manage to slip in a delightful dance duo for Dot and Adam. Despite the play’s flaws, the overall effect is very winning. The audience loved it. Running time: 2 hours, 15 minutes including intermission.