Parents raised their son to three years old and his son died. How do you explain this fate in Buddhism?

According to the Buddha's theory, children can be roughly divided into two types:

(1) Parents' kindness in previous lives, and children in this life come to repay their kindness.

Children who come to repay their kindness will be obedient, filial, hardworking and bitter, and finally reflect filial piety and harmony ~

(2) The parents' past sins in this life, and the children in this life come to collect debts.

Children who come to collect debts will make trouble, run amok, be overbearing, die young, die young, go to jail and so on. In the end, parents will be bedridden and childless in their later years.

Whether it is good or bad, it is life! As long as it is fate, it is a kind of practice in this life, or cultivate parents, or cultivate yourself, or cultivate future generations ~? Abandoning evil and promoting good, whether in this life or in the afterlife, is unfavorable ~