And yet we're kind of being set up for that with Bella, Jill, the Sage/Chad relationship, Quinn, all keeping some sort of secret from the MC and others that will likely have game-changing ramifications.
People keep secrets from each other and aren't always 100% honest with their friends and relatives when they talk to them, and half-truths, false truths, and no truths are an aspect of "normal" conversations between people. You can be having a conversation with a good friend and ask them how they are and they'll respond with, "yeah, I'm doing fine", not, "I'm having a really hard time with my crippling debt, the possibility of losing my job, and the crushing reality of being a single parent".
There are times where you can't or won't share certain details about your life, especially if it's something that you find difficult to talk about and even moreso with a new person in your life who you're still not sure about.
If you want to go pure 100% CHICK by making all major CHICK decisions, then no, but you can accept her number and then choose the CHICK option for all other major decisions, so it's still a CHICK route but with 1 major DIK decision.
- Neil is portrayed as a caring, loving, and protective father and keeping the MC's lineage a secret could be something that fits prefectly well within that type of character if he believes that it is in the MC's best interests to keep him away from the wealthy family of his mother. There are plenty of ways in which he could have ample reasoning to keep it from him if he believes it's the right thing to do because that's what parents do; they make decisions based on what they think is best for their child.
- Neil could hide the fact that she came from big money, yes, but I think he's quite proud of the fact that this woman from a completely different economic and societal class fell in love with him and even left her family behind to be with him, which is why he tells his son that part of the story because it's inspiring.
- The MC might not care that Jill is a Royce legacy, but it would be a whole different feeling if he were to find that he is a Burgmeister because this affects him much more directly and having that kind of information would turn his life upside down as a result, whether he wants it to or not. It's not "shitty soap opera level drama", it would be a pivotal key change in the story that could have very interesting and important ramifications overall that actually make the story better.