Nah, he does it for the audio section of the radio, and erroneously clams that it improves the audio. Which is of course - a load of horse crap.
Audio grade caps are used to improve the 'slew rate' (their ability to recharge faster in order to keep up with complex recorded music - as an example) of the capacitors to hold ultra fidelity under demanding critical transient peaks. Which of course does not have even a remote chance with radios. It cannot improve its response, since it has no real bass or an audio amp powerful enough to demand such a cap. Not to mention, the audio coming out of radios is far from being in the same league - by a far cry
Even if you replaced the stock caps with crappier caps, there would be no noticeable audio change. It is just busy work to charge customers more for his work, and absolutely nothing more. But you can bet that he will disagree and tell you that he can tell the difference and his customers will too. The king isn't wearing any clothes - so to speak. Sorry Snake; but the truth is what it is . . . IMO . . . Whaa - wha - whaaaaah . . .