Anger and frusteration. The first reason behind this is Physical pain or discomfort.

Bad or discomfort during sleep. 90% of their anger and aggeression is gone if you help them with this

Frustration of forgetfulness. It is very strong in intellectuals.

When a mathmetics professor went indementia, he became unbareble

I asked him if he as started forgetting things. He said yes and when he is unable to perform simple mathematics he gets frustrated and tears up all his books.

One has to find an alternative for such situations. Identity and recognition. This can also cause anger and aggression.

They become very dominant, aggressive and demanding. You can see their adamancy.

Language deficiency is also one of the reasons. Patents who are affected by this, who are unable to deliver verbally develop this frustration.

Need for warmth and belongingness. Their children are busy due to WHF and grandchildren due to online classes.

They would sit alone in the TV room with no interest in it, As they need warmth