If it ain't on the page, it ain't on the stage.
Richard then would have no knowledge of who Jason's father is, especially if he has to ask if Lois ever loved Superman. Admittedly this is thrown into shadow by the fact that Lois lies. She lies to Richard and tells him that she never loved Superman. She also lies to Lex and tells him that Richard is the boy's father, but we all know that's not true. We know it from the get go, we don't even need to be told. So there is some wriggle room, but I'd say not much or else you're living in your own speculative imagination and not in the script.
True. This is all
speculation. Being the OP, I have never suggested otherwise.
However, that does not mean that it is not worth talking about. When analyzing a piece of literature, music, art, or film, you have to delve into speculation in order to come to some meaning over the movie.
Many people see different things in a movie depending on how they interpret different scenes. Many movies are left intentionally ambiguous in order to provoke thought with the audience.
To suggest that this discussion is not worthwhile (which may not be your intention, yet that is how I am interpreting it) suggests that it is not worthwhile to explore possibilities in stories altogether (which, ironically, was why, in part, this BBS was founded in the first place).
My inclination was that nobody knew who Jason's real father was until he saves his mother with a piano. Richard is his own kind of hero and he acts toward Lois' love for Superman in the only way that a man who truly loves a woman can, by delivering her to her heart's desire. He may feel secure in the knowledge that Superman is an unrealistic guy to consider having a relationship with, but I doubt even that much and it doesn't matter.
And this is your
speculative imagination. There is nothing in the script that outright says any of that. However, it is worth discussing if we choose to gain a deeper level of understanding/enjoyment/whatever you want to call it of the film.
For the record, I was raised by a man who is not my biological father, but I always called him 'Dad' even after I met my father as an adult. My biodad I call by his first name. Neither man seems to begrudge the other his history or status in my life.
Which is how I would expect the relationship to be between Jason, Richard, and Superman post-SR. At least, I would hope it to be.