For the sound, you can either delete the sound from the SND or nulling the code in the character. For the latter, there's one of two methods he could've used. The most common way would be to play the sound in each win pose, so locate his winposes and look for a playsnd trigger. If not, then he's using a different method, likely putting said trigger under statedef -2 or -3, making the sound play when he's in a win state. To null a code, just replace PlaySND with Null.
Alternatively you can just comment out the entire chunk of code for it.
Can't help you much with the voicepack, though.
