In my opinion and experience this is not true.

If you compare this event chart with your chart or this of your daughter you can only find what the death of your mother mean to you both. If you want to see it in your mothers chart you have to look at directions, returns and similar technics.

In tradition the forth house often is called “the end of all things” and “the grave”. The eighth house is associated with death sometimes also the seventh. And it is warned again and again that one testimony is not enough. In your case every day your IC is on the ruler of the 8th and your DC on the ruler of the 4th but both together may mean something.

So you got a good example that both rulers spoke to you according to the death of your mother.

Sorry, I’m not sure to understand you right.

I wrote

Georgius wrote: And it is warned again and again that one testimony is not enough.

…and not one single constellation.

Now you show the synastry of your mothers radix and the transits at death. There are signs of danger (see below) but as I mentioned one has to check directions and the solar return (and the profection) and/or similar charts. If there are testimonies of death in all charts then one might think of death occurring. Transits are too weak to show such strong proceedings alone in advance.

Anyway in the event chart transiting Jupiter (supposed ruler of the 8th in transit) in conjunction with the Sun activates the opposition between Mars and Sun (in the 8th) in the natal chart. Transiting Venus (natal ruler of the 8th) sextiles the natal Asc. Transiting Saturn squares natal Sun…

Hi Fidibus
I have found timing the passing of elderly parents is difficult, there have to be three or more indications of quality & then an eclipse would pull it together
My mother passed during my 4th house Saturn return, although I link my tenth house with my mother & 4th with my father, still a 4th house Saturn return speaks of a difficult period a loss to my father. It was a lunar eclipse in my 5th house which heralded the passing of my mother, why the 5th?Well, the 5th is the 8th from the 10th house the house of death of the mother. So the Saturn return is when Saturn is in the sign of his return but this can be a long period & it would need to be in a relevant house or co-present to a relevant planet, so not all returns mark passing times. In addition, I had transiting Pluto entering the orb of my natal moon by opposition & the lunar eclipse was over my natal moon. So many things need to come together to strike the right chord just like you need 5 fingers to hit a chord on a piano.
My father passed when Saturn made another return, only this return was when transiting Saturn came to the sign of my Solar Arc Saturn which was in Pisces
where my Sun is located. His passing was 5 days after my 8th house Solar eclipse. So what was the trigger to give a more exact time?
Well in my natal chart, I have Uranus exactly on the nodes degree 13 degrees so Uranus carries the nodal energies for me. I have Mars conjunct the MC so Mars is connected to mother, when transiting Mars joined transiting Uranus mum passed. When Jupiter which natally is on the IC joined transiting Uranus dad passed.
Hope this helps