I could use some help.
My sister teaches special education specifically for children with behavioral disorders, and recently has done a lot of research on training a therapy dog. She found a great pup (5 month old Australian Shepard), signed up for 4 courses of training (beginning, intermediate, advanced, then if she passes all 3 therapy dog training), and has been told her pup has all the signs of a great candidate for a therapy dog.
The problem is she is temporarily living with my mom and her dog. We're not sure his breed, but looks like a schnauzer shitzu mix. He's good with most dogs, as a normal dog, but hates my sisters new dog. She can't walk by without him growling and apparently baring his teeth. She's with my mom and her dog for another month, and they're just trying to make the situation work in the meantime while not hindering the therapy dog's training. She's read a lot into how another dog and negative behavior can completely ruin a chance at her becoming a therapy dog. They have a lot of time and patience to try different methods at the moment, does anyone have any insight as to how they can make this work?
Currently she's taking the therapy dog everywhere on a leash while my mom controls her dog.