Can anyone help me with a question about Yahoo Texas Hold em Poker game?

Don't worry he can't see anything on your facebook page unless you add him as a friend there too. Basically it just means that if you are playing poker you can click the friend on and if he is online and playing poker and not playing with another group of people he will be added to the game that you are beginning. It is not a big deal and I think you can remove him too.