I have 8 years old Australian Shepherd. I used to live with my ex that owns two dogs. We broke up and I took my aussie with me. Lately he seems to be depressed and lonely. I am not sure if he misses his playmates or my ex. I found a dog that I am interested in adopting. He is aussie/husky/lab mix 9 months old. I'm little afraid of the age difference. Do you think it will be a good idea to getting a young dog to be playmate for my older dog?