I would tell your friend to take her first to the vet to find out if she had bladder issues. AT 3 years old she probably shouldn't still have a nervous bladder. Make sure shes healthy "down there". Is she fixed? If not, she should probably be fixed. It may help with the peeing and also lessen her chances of getting cancer.
Your friend may also want to try crate training. Its hard though especially when the dog is not a puppy anymore and set in her ways. Only take her out of her crate to go outside to the bathroom. Also pick one avenue of potty, piddle pad OR outside... both probably confuses the little girl. Tell your friend to take her out every hour on the hour consistantly. I know this is hard to follow but it shouldn't take too long for her to get the hang of it. Its like starting potty training from scratch.
Good Luck with this!
