I am seeking to reconnect with my estranged father of 20 years. I found an entry in the phone book that could potentially be his father (my grandfather). The name matches and it's a 20 minute walk to my father's old high school so it could be him.

I've never met my paternal grandfather. My mother and father were not married (just dating) and it ended badly so I never met his side of the family.

I believe that my paternal grandfather knew of me, but never reached out. This could have been due to some things I don't know about. I only have one side of the story. I am going to call him to ask if I could be put in touch with my father or to at least confirm that the address is correct.

I was thinking of saying the following:

Hi there, could I please speak to XYZ?
Hi XYZ, do you have time to talk?
I'm not sure if I have the right person or not. Do you have a son named ABC
about 52 years old?
Oh great, my name is EFG. I'm ABC's daughter from 1988.
I am seeking to reconnect. Are you in touch with ABC?

OK, I just wanted to put that out there. Now that I know I have the right person, I'll write you a letter.

I can see 4 possible outcomes to this phone call:

1. He forgot about me and never thought about me and could be bewildered and in disbelief. He might not believe me.
2. He has thought of me and will be angry.
3. He will be neutral/indifferent and might be a little nervous
4. He will be happy

How can I gracefully navigate 1, and 2?