Don't give up on your mission of mercy. You have surmounted the biggest hurdle by finding M. The rest will take a bit of patience. Despite the cold, Shelby will probably be okay for the time being. C&S had excellent advice. You must be careful so not to scare Shelby, because -no matter how nice - a scared dog could bite. The process of gaining the trust of Shelby may take several days. The tastier the treats the better.