Bill's father was physically and verbally abusive to Bill's Mom and Sister - never to him, but he had to sit by and watch, unable to do anything until he hit his teen years. His parents did divorce when he was fairly young but his father continued to come around. He has used anger to get his way - usually the silent treatment. I think the dementia has unleashed some of the anger he had managed to keep under tight control. Just my uneducated guess. That was a good article.

CKD is chronic kidney disease. He is Stage 3. He also has problems with veins in his legs - valves don't work well. Recently showing signs of Bradycardia (slow heart beat) and has had arrhythmia for years (not requiring treatment). He does take medication for gout; high blood pressure - which is very low now; and a thyroid problem. Those are all under control. His biggest problem is he became inactive ten-fifteen years ago (claiming he hurt too much to do anything). Doctors tried to get him to do therapy; exercise; move, etc. but he wouldn't. Wouldn't go to family functions - basically isolated himself. I would go without him, which made him madder than all get out so silent treatment when I would get home.
Doctors are sure if his anger is part of the dementia or just being a 'grumpy old man'. Trying to figure it out so they will know how to treat him.