He IS losing his sight. He has cataracts on both eyes, and I believe he may be hard of hearing (the reason for his loud barking). But I've noticed this bad behavior for quite some time, even before they came to live with us. My wife feels like she is caught in the middle. She feels it's between her folks and I (it puts me in an uncomfortable situation) The dog has also snapped and growled at her (but hasn't bitten her yet)