Don Quixote? What a beautiful dog, I cannot believe anyone would abandon him. You are a treasure to have taken him in and rescued him. I have a Chiweenie, a cross between a Chihuahua and a Dachshund, but he thinks he is a Doberman. My son named him Tony, he looks and acts like a Mafia enforcer, short and stout, kind of like Luca Brasi, the enforcer from the "Godfather," my favorite movie of all time. I call him Tony the Nose because he uses his nose the hide his treats in the blankets and to nudge me all the time. I also have a miniature black Poodle. His name is Little Brother.
What breed of dog is your other dog? Looks like he is curious about the new member of the family.
PHG