Animals can do so much for folks who are depressed. Many years ago a friend of mine had a brother who needed open heart surgery. At that time the surgery was quite new. Anyway he had it, survived, came home and was very depressed. Then his sister came home with a kitten. The kitten and the guy were home alone during the day and the guy started out playing with the kitten and then building toys for the kitten and made a neat bed for the cat. The man finally realized his life could go on and he eventually went back to his full-time job as a carpenter.
That's why they have so many animals in Retirement and Nursing homes nowdays. Animals can add so much to our lives and just the act of holding one and petting it can calm us.