Rationally and logically it makes no sense at all that someone would harm their 84 yr old relative.
But when it does happen, we usually find there were longstanding grievances and resentments. And then one divisive event happens that agitates everyone until someone is triggered beyond the point of no return.
Here is a HYPOTHETICAL scenario....does not have to refer to any specific family member in this case----but it is the kind of scenario we sometimes see in family murders...
The elderly matriarch or patriarch has some leverage because they have some money and some goods. And one of their children or grandchildren or nephews, etc, begins to feel disrespected over time.
They stay close and stay in touch because they know at some point they will inherit something valuable----or maybe they just want validation and acceptance.....but they feel rejected much of the time...Or they feel a sibling or a cousin or someone else always gets the validation and the rewards.
Maybe at some point they began asking for what they want or need? Maybe their business is going under or they are behind on their mortgage or whatever --but it is very stressful.
The matriarch has the ability to help them but maybe they deny the request? Maybe the perpetrator begins to feel disrespected and taken advantage of because they feel they have done a lot but don't get enough in return?
One day they feel emboldened and ask outright, Will you help us pay our past mortgage debts today? We are desperate......l
It can go sideways really fast. Panic sets in and then a cover up is needed. The crime scene is staged. Decisions are made in the chaos.
The decisions make no sense. ...but it is what it is...