Well, after he buys a RUM...
I believe feds hold back 25% as a withholding but
most states don't...but both fed and state tax it at ordinary income (so watch out for the state piece!). If he's 18, he's actually in a good time to win it given presumably low marginal bracket.
His biggest asset right now is time + lifting his earning potential, so I'd bend a healthy amount that way towards education.
If he were my kid and he had reliable transportation, I'd suggest ratios like for the final "investable" amounts (ie, post tax, post tithe if that's your thing) go into:
1) 40% towards education...trade school is a decent idea.
2) 20% starting up a ROTH (if he has any earned income for the year received...lottery earnings don't count as earned income), and get the seed germinating that putting money in there every year is a good idea. "Index funds only" rule.
3) 15% towards building up an emergency 6 month fund (we all need it!)
4) 15% starting a "house fund" (agreed with
@Wildabeast on the rent comment)
5) 10% fun money (he is 18 after all)