Should one first abandon sins before abandoning heresies, and how can one reconcile this, given that the father compels the questioner to observe some heresies and describes him as deviant for abandoning them?

You must be dutiful and kind to your father, even if he adheres to innovation (bid'ah) and misguidance. You must advise him with wisdom and good counsel. However, you are not obliged to obey him in matters of disobedience [to Allah]. The sins you commit, such as not praying in the mosque, masturbation, and conversing with girls, are things your opponents will use against you, turning them away from accepting your advice. You must avoid both sins and innovations, for innovations are more dangerous than sins and more hateful to Allah.