Sorry it took so long to reply Ive had issues with my password.
I have sent another email to the breeder who owns my dogs mum. My next step will be to email the fathers owner who is a seperate breeder. Hopefully I at least get a reply.
I'm certainly not looking to send him back or anything like that. But I do hope if its something that could be prevented for other dogs and families than that is my main goal.
Thank you for all of the information. I will look into the antihistamines and hope for at least a little bit of relief for him.