Is it permissible to marry a divorced woman who is older than me and has children, and is there reward and merit in raising and caring for them?

There is no objection to marrying a divorced woman with children if the marriage contract fulfills its conditions and its legal implications follow. The Prophet, peace and blessings be upon him, married divorced women who had children, such as Umm Salamah, may Allah be pleased with her. There is no evidence for a specific reward for marrying a divorced woman or caring for her children, but it is an act of ihsan (goodness) for which the doer will be rewarded if he seeks the reward from Allah, "Indeed, Allah loves the doers of good."