Adding a third dog (20 characters)?

Currently we have two fixed females. They get along with each other well. one is 11 (westie) and had a stroke and her hind legs are paralyzed, but she can still run around and will occasionally play with my younger dog who is 3 (king charles spaniel.) The younger one likes to bother the older one a lot, but she doesn't really care. They both are friendly with other dogs. The third dog would only be temporary. My friend's landlord is making her get rid of the dog, so she wants to keep the dog in our care until she can find a house that will allow her to keep her dog. He is a male , a year old, and some sort of hound. He is really energetic and playful. Do you think they could all get along for a few months?