Incomplete Rainbow

So my brother is colourblind.
Oh i'm serious. This is not the opening line of a joke or anything; my brother is colourblind.

Contrary to what the name of the 'disability' might suggest, a person afflicted with colourblindness is not unable to percieve any form of colour entirely; he/she is just not able to differenciate between what may appear as very similar hues. Between blue and purple for example, or even red and brown. 

I like to attribute the discovery of my sibling's shortcoming to myself (thanks, very much)..to 15-year old me actually. It's not rocket-science really. I didn't have any suspicions and hold up some colour charts to his face or anything. I just happened to stumble upon 11-year old bro sprawled on the floor, colouring the pacific ocean in his history map...purple.
Now, my brother is a trouble-maker, but not in a "Hah take that!" sort of way. He's more likely to set up camp in the 'wrong-place-at-the-wrong-time' category. That's why i figured his violet equivalent of the Red Sea wasn't intentional. So after stopping him from creating what seemed like a diseased ocean, I held up some colour pencils for him to differenciate. On coming to the conclusion that he really did have a problem, we marched over to tell the folks of our breakthrough. It took a while to get dad to take us seriously, but mum was in denial..she still is.
There really is nothing you can do to change the fact that you're colourblind. Perhaps maybe, an operation of sorts, but it really isn't a life-changing discovery. We did have to make some minor alterations to our lifestyle however.
Firstly, i had to be sure that brother dear wouldn't mistake my toothbrush for his (we share the same loo). So whenever we did buy a pair, i'd go out of my way to make sure that the colours were as far apart on the spectrum as science would allow, even if it meant mine being a garishly yellow brush while his was a dull blue.  
Another thing we learned was never to ask him to bring us a green colour pencil (hey i used them in school!) or a green folder, because the poor chap would just as innocently get us the brown one.
Strangely, he's never had an issue matching his clothes. Although at times he does need a little advice on whether this tie goes with that shirt. But then again who doesn't right?
I asked him once if he could decipher when the colour of the traffic lights changed from red to green (or vice versa).
"Even if i couldn't," he declared, "I can see the lights change can't I??"
I knew that! I was just..erm..checking.
 

Cheers.