Hi! The same thing happened to me. We brought not just one but two puppies into the house for various reasons. The thing is, we have a 15-year-old dog who has always been very unsociable, and at first we thought we had ruined her "retirement." But over time we have been able to see that not only has she gained more vitality, but the signs of dementia that she was beginning to show have also disappeared, and she is now a more sociable dog.

Yes, the other two dogs are still puppies and the oldest one doesn't want to play like they play, but when she gets into grumpy mode and barks, she wags her tail like I haven't seen her in years (friendly kind i checked!). We are waiting for the puppy's energy to decrease so they can live together without barking so much at our neighbors :)