If your fading is working and your dad can live with it, carry on as you are and maybe lessen up even more. If he is old and feeble he's not likely keeping tabs on you in any case. Just love and care for him like a son should under any circumstances with a loving parent(I am assuming that). Unless you are forced to take him to meetings or something, I doubt it is hurting you too much to give the org some lip service.
Take care of yourself, your dad and the people you love. Don't kill your spirit to do it though for others. You need to remain whole.