A problem I am facing is I am from a broken family. My father divorced my mother a few years ago. He (my father) divorced my mother after 23 years of marriage. My mother had no other way to marry again because she was quite helpless at that time. None of her children, including me, were able to do anything for her financially. To solve this problem, she married again. Is it permissible for the mother to visit her children in the home of her ex-husband?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is allowed in Sharia for a mother to visit her children in the house of her ex-husband if she feels safe from seduction and if she takes all precautions to avoid mixing or being alone with him since he is an alien person to her.
However, it is recommended to meet in any other place if it is possible to avoid hurting the feelings of the recent husband and also to keep away from those who do not fear Allah in accusing others.
Allah knows best.