I'm sorry you find yourself in circumstances that trouble your heart.
I hope that you find peace with whatever you decide to do and that the outcome is the best and healthiest for all involved.
That is a tough one.
I would certainly want to know if it were me.
Given things you have said such as him never listening to you, him living in denial, etc., I would have to wonder what good could come from telling him...but like you, it would still weigh heavily on my heart. He's your Dad, after all, no matter what!
Again, I am sorry for these circumstances. My best wishes for him and you both, for peace and happiness.
Peace.
ETA: meant to mention that I agree with redatlanta as far as evidence being circumstantial...and that people can easily talk their way out of circumstantial evidence, especially if their partner prefers the comfort of denial.
