Plead guilty, turn up at court (turn up as early as you can, its first come first served!), dress smart, be humble, magistrates are human dealing with this sort of thing day in day out, don't say "caught speeding" it implies you do it all the time, but this time I got caught out, Impress on them that you made a mistake and your here to deal with the consequences. Expect the worst and hopefully your be relieved when you get a fine and points, magistrates have a set of guidelines that they have to stick to which can be found online with a bit of searching, how leniently they apply them will be determined by previous record and peoples attitude on the day. Its a myth that if you need your licence for work you can't be banned because their stock answer is "if you knew that! then why were you speeding putting your lively hood at risk?"
I wish your brother well, I speak from personal experience of a few months ago and having never been to court before it was a pretty stressful experience made worse by the fact its your own fault. All you can do is learn from experiences in life and be more careful in the future, we all know speed limits in certain areas are ridiculously low and quite rightly low in other areas.
