Our miserable-looking guy must be Sean Harris, villain of the last two Missions: Impossible. The miserable old man is his uncle, Alun Armstrong, a Dickens miniseries regular currently appearing in a Martin Freeman show called Breeders which is annoyingly not about the careers and home lives of the Deal sisters. These two speak in unsubtitled British, when they speak at all.
Sean has trauma… and a Babadook picture-book of his trauma… and he carries around a satchel with a trauma-spider inside. I guess Sean finally stands up for himself, pushes his uncle aside and frees the local kid that Uncle had imprisoned. That brief burst of energy comes at the tail end of a long movie of people walking in a horrified daze through their miserable lives. Holness is Garth Marenghi, and having successfully proven he can make very serious things, I hope he dials it back a bit, or combines his talents a la his costar Richard Ayoade.