Florian Zeller's The Father (2020), originally written as Le Père, explores the psychological deterioration of an aging man, Anthony, whose dementia disorients both him and his daughter, Anne. The play, translated into English by Christopher Hampton and adapted for cinema by Zeller, immerses the audience in Anthony's fragmented reality. Zeller uses subtle changes in the apartment's setting—such as shifting furniture, characters, and dialogue—to mirror Anthony's unstable mental state. This psychological approach reflects the complexity of dementia, allowing viewers to experience Anthony's confusion, loss, and illusions firsthand. The Prague School's theory of stage semiotization informs the film's adaptation, where the actor's body and environment acquire a symbolic meaning beyond their physical representation. As Anthony objectifies his daughter, Anne, treating her as an object of daily need, the film explores the depersonalization that often accompanies dementia. Through psychoanalytic film theory, The Father also reveals its cathartic and therapeutic effects on its audience, engaging them emotionally with the characters' mental and emotional states. Lacan's theory of the Mirror Stage is applied to understand Anthony's regressive state, in which his reality distorts and fragments. At the same time, Stanislavski's shift from Emotional Memory to the Method of Physical Actions emphasizes the actors' emotional expression depth. Ultimately, The Father illustrates the emotional and psychological toll of dementia, offering profound insights into caregiving, familial relationships, and identity.