This means she did not do anything else...she did little more....not much more....than just taking care of him and the children. That's about all she did.

she spent her time doing little more than taking care of him and the children = She took care of him and the children most of the time.

what it means when someone says "she spent her time doing little more than taking care of him and the children" ? = CORRECTION: What does it mean when someone says, "She spent her time doing little more than taking care of him and the children"? "She" is probably a housewife or a caretaker. It means the woman was totally devoted to caring for a man and his children, including cleaning, cooking, and doing their laundry. Such a woman often sacrificed her own wants and needs. In the U.S., this was often true of housewives in the past.

她把自己的大部分时间都用在照顾他和孩子身上了。

I got it. thanks so much for your explanation guys