In Florian Zeller’s “The Father,” Anthony, 80, in the grip of dementia, is a captain ready to go down with the ship. Overhearing his daughter and son-in-law contemplating a nursing home, he curses them as “rats” abandoning him. Pacing his London apartment in a bath robe, he mounts a noble resistance. “I am not leaving my flat!” he shouts. In staging and perspective, “The Father” mimics the disorientation of dementia. Anthony, a regally theatrical man played by Anthony Hopkins, is an actor who every time he takes the stage, the scene has changed before him. Timelines, settings and faces are all kaleidoscoped by a splintered memory. His ship — his flat — might not even be his.