Is this a recent development? I would recommend a thundershirt, but be aware you need to put it on the dog BEFORE the storm hits. Medication can also help.
Beyond that, I would work on desensitization with sounds.
Additionally, I’d like to add my Doberman was not sound averse until after her spay, and she slowly increased in her storm aversion. She went from a dog who would stand outside and glare at the sky for daring to make noise when she was intact to a dog who’d cower on her bed post-spay. It was bizarre. We worked on desensitization training with Youtube videos and the highest value treats I had – bits of medium-rare steak. It helped.
Hey there.
I’m so sorry to hear about this. It’s not easy, watching our pets go slowly.
After Dr. Magnifico posted about this awhile back, I had a list of Things my cat liked to do. As the list shrank, I knew we were closer and closer to letting him go. My list included eating, drinking, cuddling, playing, etc. I would make a similar list for your dog, and monitor based on that.
For the puppy, I would honestly keep them separate when pup is acting like a puppy. This could be as simple as tethering him to someone when he can be supervised (something I recommend anyway for the first 6 months to help with housebreaking and general naughty behavior) and crating when he can’t.
Thank you, Laura!