13 y.o. Is getting more stubborn and disobedient
I have a 13 year old mini schnauzer. He has cataracts and is slight deaf. When he was a puppy until older, around 10, he was very disciplined and obedient. However I find in the past couple of years he has become very stubborn, starts to growl and even snaps when I command an order. Can you please recommend what I should do as he is quite disobedient now with commands and not listening. Thanks in advance.