You realize that the black hat/jacket lifestyle is not for everyone. You say “in general”, but there is no inyan to where it when not davening – that’s just a shtus that came about recently.
If your child is keeping shabbos, keeping kosher, and putting on tefillin every day, be happy for that. Pushing him can make him stop with those also.
Yes, I’ve had exposure to this so-called problem. The real problem is when people tell you you’re not frum without the hat and jacket.