Is it permissible to divide an inheritance equally among family members (the mother, two married sons, and a married daughter) without adhering to the Sharia-compliant distribution, given that the estate consists of money in a bank account and the family agrees to this?

It is permissible for the heirs to divide the inheritance by mutual consent if they are adult and of sound mind, but it must be believed that Allah's division is the most just and best. It is forbidden to deviate from it out of dislike for it or belief in its injustice. Usurious gains are not included in the inheritance.