How can filial piety be achieved, especially in light of parental separation and changing life circumstances, while avoiding disobedience to parents, and what is the ruling on leaving the father's home to achieve personal independence and avoid family problems?

You erred in obeying your father by not visiting or calling your mother for fifteen years, for there is no obedience to a creature in disobedience to the Creator. You must repent to Allah for your negligence in maintaining ties with your mother throughout this period. If you cannot visit her weekly due to your work, there is no blame upon you, but inquire about her condition via phone to compensate for your infrequent visits. We advise you to be patient with your father's harshness and anger. Your father has no right to prevent you from marrying and becoming independent if you are in need, and there is no disobedience in that unless you are able to combine marriage with remaining with him.