The new film “The Whale,” which A24 will release on Friday, is about a man named Charlie. He lives alone in a squalid apartment in Idaho, grieving a male lover, and is estranged from his ex-wife and teen daughter. His only companions are a nurse and a young evangelist who shows up at his doorstep. Charlie teaches an online essay-writing course, but he keeps his computer camera off out of shame, because he weighs around six hundred pounds.