Should a will be executed for a man who passed away leaving behind children and a wife, when a written will was found from him dating to before he had children, and it did not mention anything about his money for his children?

This will must be executed if it is within one-third or less [of the estate's total value], and it is not for an heir unless the other heirs permit it, in which case it is executed from the share of whoever permits it. If the beneficiary accepts it, and it is something permissible to benefit from Islamically, then it is disbursed from the principal of the estate, and the heirs have no right to it.