How to Mute Someone in CS:GO
The Optimal Audio Setup For CS:GO
These are all the ways to mute a player in CSGO
How to disable chat in CS GO: text and voice
How to disable and mute radio commands in CS:GO
Steam Community :: Guide :: How to: Disable chat in game (hud_saytext / hud_saytext_time equivalent in CS:GO)
This form of disabling is recommended if you have to do nothing with voice chat at all.
You can test this sound by playing with bots.
Muting him will only block voice and text communication, you will still see and hear his radio commands.