IMac User
The main thing your friend needs to do is to make sure that he has the latest up to date version of "Flash" installed on his IMac and make sure his browser and other programs are also up to date. Adobe Flash is a free download so just update it.
Also their is a great Snooker Channel on YouTube for watching almost live events, check out the "Snookerroomru" channel. I just watched most of the UK Championships on the channel this past week and although it is not "Live Stream" he gets the matches posted almost immediately after they are finished.