Death of the Mother in a chart
I would suggest that you calculate several charts -- perhaps for 6:15, 6:45, 7:15, 7:45, 8:15 and 8:45. Then--
1) Look to see what planets are in the 4th and 10th houses and the MC and IC angles. This axis relates to the family. Often the mother is the 10th house, the father is the 4th house in terms of how a child views the family. Yet, the home is the 4th, the family status and well-being is considered to be shown by the 10th house.
2) Look for the sign-rulers of the 4th and 10th house signs. Where they are relates to how the roles of the parents are modified in terms of their attitudes.
3) Look to the Moon's placement in the chart. The Moon's house may reflect the role of the mother and the needs one feels relative to the mother in terms of how one feels about her, depends upon her. Aspects to the Moon by other planets will show how you relate to her -- squares being stressful, etc. These aspects may or may not change or become more/less acute over the few hours of time that you believe this person was born within.
Using only the Moon or the rulers of the 4th/10th angles or the planets close to those angles, look for either --
4) Transits to those planets by Saturn, Neptune especially.
5) Transits over the Asc. or Desc. angles. If the death was due to old age, look for Saturn or Uranus. If the death was unexpected, look for Uranus. If death was due to infection, Mars or Neptune or both. If due to a heart condition, the Sun, Mars, perhaps Jupiter. If due to a blood condition, then Venus. All of the typical planet keywords will clue you into the situation.
There are many other tools that an advanced studies student would use such as various progression techniques, solar and lunar returns, and other types of charts but each of those has to be read in special ways which may or may not be known to the majority of those who follow this forum, and which would take too much time and space to cover here. Hope this helps. Dave