Can immobilize, if not completely stop a 6' tall fellow like he was. At least slow him down a bit if hit in center mass.
Anecdote of course, but my great-grandmother lived to just shy of her 100th birthday and would have definitely been able to handle a small revolver. She was born on a farm in 1885 and lived to 1985 still driving her 1947 Ford coupe until age 91 when her eyes began failing a bit. She told of growing their own food, hunting, fishing, butchering/cleaning and making just about everything themselves as a child. Hard work. Granny was taller than this Brit woman but a firearm is a great equalizer.