Some random thoughts on how her mother's death might have influenced Deborah's future behaviors and/or motherhood:
*Besides caring for her two younger brothers, DB probably felt like she was expected to assume the other duties of the wife/mother in the household - cleaning house, cooking, doing laundry, etc. This would be lot of responsibility for a high school student, so I'd like to know just how much she was expected to do or if her dad hired someone to take care of the house, cook, etc.?
*With a lot of responsibility thrust upon her to care for her younger brothers and/or household chores, Deborah might have not had time for the usual activities of a typical high school student. DB might feel that she was deprived of her teen years, hence the reason for insisting on "adult time" when she is caring for three young children in the Irwin household.
*Since Deborah was put in the position of caring for her two younger brothers, she may have enjoyed the "only daughter" status in the family if her dad doted on her especially after the loss of his wife. Perhaps DB feels a special maternal bond with her son and JI's son because they are the reincarnation of her "younger brothers" and the relationship that she had with them as a teenager. Baby Lisa might have not been as welcome into the family unit as some might think. jmo