I agree with the others...don't get a pet store dog...either go through a rescue group or a shelter dog if you can. Also, you might check into the service dog groups. They may be able to train the dog not just to behave for your mom, but to help you if your MS gets worse. My wife had a friend who trained service dogs and they could do some amazing stuff...let themselves in and out doors, bring the phone/tv remote/beverages from the fridge, go get medicine bottles, etc.