I agree that because there are unique family situations and dynamics, this specific topic is very different from family to family.
My father is a successful entrepreneur himself, in a completely different line of work. In high school, there were times when I think he doubted my work ethic (but I found something I love to do and I do it very well) and I have this nagging inside me to share with him how successful we have been at saving, investing and planning. They know very well that we have been fortunate, worked hard, have no debt, etc. We get a nice Christmas check each year from my parents, and they always make sure that they do things evenly for me and my siblings, so I don't really fear or think it would change anything along those lines as my siblings have each had their own success and are doing well.
My parents own their own business and dad is very "numbers" driven and something in me wants that validation of sharing with him as I think he would be astounded that we had 2.3m in investments.
Because you said that your father is a successful entrepreneur himself, is numbers-driven, AND because you say that you think he 'doubted your work ethic' (but what parent hasn't?
) and that you entered a completely different line of work, I have a feeling that he would be impressed with your fiscal accomplishments.
However, I wouldn't necessarily do it over dinner.
Perhaps just start out by bring up a general finance topic. Maybe talk about something that was posted on the ER forum, and say "Hey dad, I read this story/comment on this early retirement forum I visit a lot....". It would naturally lead into a topic of "ER??!? Why the heck would you be reading an ER forum?" Or, just simply start talking about investments, and some stock you recently bought, and ask him if he had any good investment ideas lately.
You could eventually arrive at simply asking him "so how much do you think I'm worth?"
Given what you've said, he'd probably guess low, at which case you could mention the approximate number. My guess is he'd take a stab at a cool million, since many people have a hard time adjusting to income growth, and still think it would take as long to reach a million with today's higher incomes versus when they were starting out.