Mrs Gaskell's brother

SPOILERS:

One of the end-of-book notes in my copy of Cranford says that Elizabeth Gaskell had a brother who sailed away to sea and was never seen again. It's sort on interesting, that. In Cranford there's a brother who sails away to India. In North and South, there's a brother who enters the Royal Navy, is court-martialled, and has to take refuge in Spain. Both brothers are older and much loved. Both brothers eventually come back, at least for a while. Her only other book, I've read is Mary Barton. There's no brother, but there is a witness who sets sail from Liverpool, and Mary has to catch up with the ship before it gets away, otherwise an innocent man will be hanged. It's as if Mrs Gaskell's brother was always on her mind.