I do not recommend the "L" or "N" frames for ladies. A whole lot of weight and not much else that can not be found in a lighter package. My recommendation ,and what has worked in the past, is a "K"frame S&W chambered for the 38 Special. M10, M12, M15, and all the stainless numbers give you a lot to choose from. Nothing to heavy and much easier to hold than any of the other frames sizes.
But it is all up to Mom.