I agree -- try Oxy-Clean a few times, and go ahead and give it to your Dad. Time is more important that color.
I made a quilt like this for my Dad toward the end, and he wished it could have had it sooner. I still cry when I look at that quilt, because now he is gone. Bottom line? Your Dad will love anything you have done for him, no matter what color it is. You could even try the Oxy-Clean.... later. Spending time with your Dad now is more important than making him the perfect quilt. Take it from someone who has been there.