GG:
The situation with cricket is complicated because, while Sky hold the rights to broadcast all home England matches, it's BT Sport who hold the rights to some other games. (So, for example, anyone who wanted to watch the recent Ashes series live from Australia couldn't get it via Sky or with a Now TV Sport Pass; they had to subscribe to BT Sport).
Unlike some other sports, rugby doesn't have its own dedicated channel with Sky Sports. It's shown on Sky Sports Action, along with tennis, boxing, darts and other sports (including things like Gaelic football and netball).
However if GDG wants to watch all of the cricket coverage that's available on Sky, plus all of their rugby coverage, he can either pay £22 per month for the 2-channel deal (as above) or, if he's prepared to sign up to the 18 month contract deal mentioned by Everhelpful (which goes up to £25 per month once the 18 month period has ended), he can get all of the Sky Sports channels for £20 per month. (In both cases that assumes that he's already got the basic Sky Entertainment package because the sports channels are add-on to that).
If he
only wants sports channels (i.e. he doesn't want any other Sky channels at all - and you don't either) he might be better off by cancelling Sky and paying £33.99 per month for a Sky Sports Pass with Now TV:
http://www.nowtv.com/watch-sky-sports-online