There’s something hectoring, mawkish and underpowered about Stage Mother. Jacki Weaver plays Maybelline, a small-town Texan housewife who is the choir-mistress at her local church. One day she gets the grim news that her son – a drag queen from whom she and her conservative husband had long been estranged – has died of a drug overdose, bequeathing her his San Francisco drag club.

So Maybelline comes to the big city on a sad, late-life personal mission to make peace with her son’s memory; she meets his partner, Nathan (a rather ponderous performance from Adrian Grenier), and all the other drag queens. Their life-affirming exuberance causes her to question her past attitudes and she winds up staying for a while, renting a room from single mom Sienna (Lucy Liu), and she makes the queens an offer: she will teach them to sing (as opposed to just lip-sync), and they are thrilled by her instinctive motherly affection and Texan sass. Under her inspiration the club starts to become a big hit.

It’s all perfectly well-meaning with an unimpeachable message of acceptance and love, together with building a better life through musical self-improvement. But nothing really comes to life and the dialogue is plodding and laborious. Maybelline has an unexpected romance with a hotel concierge (the sort of role that Héctor Elizondo played in Pretty Woman) though there is something by-the-numbers about this unlikely gallant encounter as well.

• Stage Mother is released in the UK on 24 July.