He has actually confirmed a couple of times in the past that David won't be getting a route any time soon since he's already dealing with 4 routes and especially because David isn't even 18.
(Also, side note, I understand that getting no reply is a bit frustrating but keep in mind that this visual novel is being developed by a SINGLE person. Monchi has to write the story for the routes, draw the art, do the coding (Not to mention the fact that the way he makes every sprite EXTREMELY expressive makes the coding process even harder to do, let alone for a single person.) and that he has his own life outside the visual novel. Please try to be a bit more understanding and patient with him, especially since he isn't even obligated to develop this visual novel in the first place since it's free to download and play.
Also, not trying to hate on you or anything, just trying to clarify.)