Here follows a fatwa from Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allaah have mercy on him) regarding the issue of obeying parents with regard to shaving the beard:
Question: Regarding obeying your father with regard to shaving the beard.
The Shaykh replied:
It is not permissible for you to obey your father in shaving the beard, rather you must let it grow, because the Prophet (peace and blessings of Allaah be upon him) said: “Trim the moustache and let the beard grow; be different from the mushrikeen.” And he (peace and blessings of Allaah be upon him) said: “Obedience is only with regard to that which is good and proper.”
Letting the beard grow is obligatory, not just Sunnah, according to fiqhi terminology, because the Messenger of Allaah (peace and blessings of Allaah be upon him) commanded that, and the basic principle is that a command is obligatory.
Majmoo’ Fataawa al-Shaykh Ibn Baaz, 8/377-378