Ariel caught Kennel Cough at 11 weeks old, 1 week after we had her. I was so scared because I never had to deal with it with my older dog. She was so inactive ... completely lethargic. Her vaccination schedule went off track because of it. I felt so sorry for her

It took her about a month to get over it.
We hope your little man has a speedy recovery. It'll seem like forever, but he'll get through it soon enough.