Is he always quiet on date, or are there cases where he is interested in the girl and is still quiet?
I think he needs some therapy in how to make a conversation, the art of, if you will.
He can ask her some quesitons, what does she do, what sort of things she likes, her family, where she grew up, school, etc.
there can be a list of things he can ask. Each question will generate a response and possibly a question from her.
Other areas of interest, travel, politics, learning, reading.
Perhaps he should keep the first date short, perhaps 90 minutes.
So he won’t run out of points on that list.
If there is interest a second date should have some activity be it a lecture, a shiur, etc. so they can discuss this.
If the interest proceeds further I believe he should tell her that his is not comfortable with conversations like that and let her decide how to take that.
By keeping his secret it won’t help.
Hatzlacha, it sounds like this is solvable.