Have I sold myself out? I probably have. Or am i playing the game to win, with regards to caring for my dad.
Only you can decide that. However if your elderly father requires a caregiver and you're it, self preservation would probably prevent him from shunning you. Thats how it seems to me.
If you decided to leave the WT and be open about it, it doesn't mean you have to harangue your father to see the light in his final years. Perhaps you could find a balance. "I dont agree with the religion but we wont discuss it unless you ask."