I assume he means how to check if a player is currently "Coaching" someone in TF2. There's an entprop for that;
PHP Code:
stock bool IsClientOnCoach(int client)
{
return GetEntProp(client, Prop_Send, "m_bIsCoaching");
}
It's as simple as that. It'll return true/false based on if that player is coaching someone.
Although I do see he has CSGO named in his profile Location but I'm unaware of whether or not CSGO has coaching, soooo...