In Hello Guest you could hear Quentin make all kinds of snivelly noises and sounds, especially at the start of the game like when he's struggling to move his bike or when he's creeped out by the statues. Then from the Alphas onward he became less vocal and in the final game he's just completely mute.
Honestly this is just a disservice to Quentin as a character, as it basically removes all the "Nerdy, lazy, clumsy, feeble but well-meaning" personality he had before and just makes him into an emotionless husk that you pilot instead of a fleshed-out character in the fictional world. And honestly I think the fact that the new updates gave even more lines to every character EXCEPT Quentin just makes it stand out even more.
In other words, I think you should give Quentin more personality by adding more voicelines to the cutscenes and/or gameplay, be it reused lines from HG or brand new ones entirely.