“My year of unraveling” is how a despairing Christy Morrill described nightmarish months when his immune system hijacked his brain. What’s called autoimmune encephalitis attacks the organ that makes us “us,” and it can appear out of the blue. Morrill went for a bike ride with friends along the California coast, stopping for lunch, and they noticed nothing wrong. Neither did Morrill until his wife asked how it went — and he’d forgotten. Morrill would get worse before he got better. “Unhinged”