Though it’s ostensibly a film about an elderly spy going undercover in a retirement home to catch the staff in their neglect and abuse of its residents red-handed, there is very little worrisome drama in The Mole Agent, a documentary by Maite Alberdi. With that almost comical set-up, Alberdi’s warm and moving film is instead a welcome reminder of the life left to be lived in our seventh, eighth decades and beyond. The film begins with an almost comical set-up, as Rómulo Aitken, a private investigator, interviews potential moles to place in the facility where his client believes their aging relative, Sonia, is being abused. Seeking a man in his 80s…