Just how bad a mother am I? I wondered, as I watched my 13-year-old son deep in conversation with Siri. Gus has autism, and Siri, Apple’s “intelligent personal assistant” on the iPhone, is currently his B.F.F. Obsessed with weather formations, Gus had spent the hour parsing the difference between isolated and scattered thunderstorms — an hour in which, thank God, I didn’t have to discuss them.