By Florian Zeller. Translated by Christopher Hampton. Directed by Mindy Parfitt. A Search Party production. At the Vancity Culture Lab on Thursday, November 21. Continues until November 30

There was audible weeping at the end of The Father, and not just from actor Kevin McNulty, in character as André, an elderly man with dementia. The tears flowed and our noses ran, and as an audience we learned new ways to be devastated in public together. Such is the power of McNulty’s jaw-dropping performance; it’s a singular achievement in a long and still-vibrant career of memorable and award-winning turns.

The audience’s heartbreak is a real testament to McNulty, because André has become, in part, a jerk with a persecution complex. He’s also a slippery character and a deeply unreliable one.

His memory is faltering, failing, and fracturing, and playwright Florian Zeller does an incredible job of conveying André’s illness through repetition, time jumping, and double casting. (Almost every character is played by at least two actors at varying moments.) This helps the audience experience firsthand André’s confusion and frustration, his paranoia and vulnerability. But it also makes his prickly humour and his penchant for cruelty all the more dangerous. He lashes out at the daughter looking after him, and his caretakers have all quit because he’s so verbally abusive and physically threatening. But what is real and what is just in André’s mind? Zeller’s script keeps the audience guessing until the very end.

Director Mindy Parfitt has an incredible command of the material. The Father marks the debut of Parfitt’s new theatre company, the Search Party, and what a gutsy, brilliant choice it is. The play isn’t just emotionally complex, it’s also structurally complicated. The Father comprises many scenes and vignettes. It’s a clever means of further communicating André’s disorientation from dementia, but it’s also a potential pacing nightmare. Not so in Parfitt’s hands. She has a deft touch and decades of experience, an important combination.

The slow stripping down of the set throughout the play, until it’s just an empty white room, is another thoughtful way to depict André’s deterioration. Not that McNulty needs any help. The whole ensemble is fantastic, particularly Jillian Fargey as André’s long-suffering daughter, but this is McNulty’s show and it is a master class in acting. The room is intimate enough that you can see how his eyes darken as André pivots without warning from seemingly genial to emotionally abusive. The fact that we can weep with André, and for him, is a testament to McNulty’s genius.