
I do not think with a whippet the sex will make much different as they are gentle breed. I think they are an excellent choice with the dog staying with you Mum during the working day, as should be easy for an older person to handle, and they love the home comforts and a warm lap to snuggle in.
Pay particular attention to training, especially recall, and alsways bear in mind being a sighthound they will want to run after moving objects, like a carrier bag, so do not let off lead near a road, as they can cover a lot of distance if they decide to run.