Must I move to Alexandria to seek my wife and her family, even though that would distance me from my elderly parents in Cairo who need my care, and would require me to change my job and career path, while there is tension between my mother and my fiancée?

Filial piety is an obligation, and disobedience to parents is a grave sin. Leaving one's parents and residing far from them causes them severe pain, especially if the son is their only child and his mother is particularly attached to him. It is obligatory to obey parents in matters that do not involve disobedience (to Allah) and to avoid anything that grieves them. It is not permissible to leave one's parents unless they are content and wholeheartedly agree, and provided there is someone to look after their affairs, along with frequent visits and inquiries about them. If they do not agree, then the wife must be persuaded to live with them, for it is not permissible to prefer anything over filial piety and obedience to parents.