The therapist I've been seeing is only a year older than my dad, so I had similar problems. I've never viewed him as a father figure because he is the literal polar opposite of my cold, controlling dad, but I've had the problem you have with being afraid of being 100% open with him due to fear of rejection. Because it's what I've learned to expect from my dad, and therefore approach all males extremely cautiously. It helped me to tell him about it. Therapy is the place to explore those feelings and deal with them. I don't know that I would have ever had the chance to deal with it anywhere else. He should discuss it with you and be helpful. Mine reassured me a couple of times that he was there to be supportive and make a safe environment--The exact opposite of what I'm used to. To his credit, he did do that 100% of the time and it was very, very healing. I hope you would be able to find the same thing in your therapist. The only thing you have to do is start the discussion. I know it's terrifying.