You have forgiven your father for his abandoning your family and you. I think you now have another situation in which you might consider forgiving your father for coming to you now, as you say, after the pressure is off for his parenting you. Forgiveness, as you know, is your choice. Given that you already have forgiven him for his past behavior, you now know the forgiveness pathway for forgiving him for his current issue. Please keep in mind that he may have a lot of remorse and guilt. He may not be asking for your forgiveness only because the pressure now is off. If you see his possible remorse and even anguish, it may help you in your decision to forgive.
For additional information, see 8 Keys to Forgiveness.