OP, the first decision you need to make is whether you want to try to make more money in the bitcoin world, or cash out into the real world. If I was you, I would do a mix of both.
This is why I recommended him this or something similar:
(SSS) - A Sane and Simple bitcoin Savings plan (btw: rpietila usually write interesting things)
https://bitcointalk.org/index.php?topic=345065.0I would cash out a certain number of bitcoins, maybe 100 or so, just enough to live comfortably for awhile.
Good idea, but on the other hand remember that he is 16.
Don't use mtgox to cash out, use coinbase or absolutely anything else. Once you cash out, BE ABSOLUTELY SURE to declare the profits as income to your country's tax revenue service.
It's a pity that he live in the UK, I know some people in Poland that probably would be interested in his coins and would probably pay in cash (with commission, of course). We should also remember that he is a minor...
If you decide to do a 100% cash out, perform the cashout over a time period rather than selling all at once.
Certainly.