There are two possible places for this, which are you referring to?
Here
if (ChatListener.isAFK = false) {
ChatListener.isAFK = true;
icommandsender.addChatMessage(new ChatComponentText("You are now AFK!"));
return;
}
If this doesn't work it is not being called.
I use that and it only comes up with the "Hello" message, not the "You are now AFK!".
Then it is never making it into the if statement, or it can't send the message try removing the help message.