What is the divorced woman's duty towards her ex-husband who does not inquire about their children, and is she required to try to strengthen his relationship with them?

If the father is remiss in the financial rights of his children, he must fulfill them and care for them, for the Prophet, peace and blessings be upon him, said: "It is enough sin for a person to neglect those whom he supports," and "Indeed, Allah will question every guardian about what He entrusted him with, whether he protected it or neglected it, even questioning a man about his household." In case of his refusal, recourse can be had to the court. If his negligence is in inquiring about their well-being while fulfilling his duties, then the mother should help him and encourage a good relationship between the children and their father.