They can definitely get a button for his first visit.
And yes, the Main Street barber shop still does cuts for a really good price.
Aside from that, there are so many tips, I'm not sure what to even start suggesting! (Mostly because I don't know what you've already told them!)
Generally speaking, let's see... going in July = HOT HOT HOT! Tell them to be sure to dress real light, maybe take a middle-of-the-day siesta back at their hotel room to avoid the hottest part of the day in the parks, and that ice water is free for the asking at any counter-service restaurant. They should plan on drinking a lot of water to beat the heat! A lot of people recommend bringing one of those
cooling towels (like Frogg Toggs brand) to help you cool off on hot days. It's also likely to rain, likely a few times, while they're there. They can bring fold-up ponchos from home for cheap (sporting goods/outdoorsy stores have them, so does Target/
Walmart/etc) or buy the Disney ones, which are obviously more expensive.
I don't know that I can be more specific unless I know a bit more. For example, how old is your nephew? What does he like?
My son had a blast making pressed pennies (he calls 'em "squished pennies") on our last visit. You need to bring a bunch of quarters and pennies with you into the parks - one easy way to carry these is to use a mini M&Ms container (after you've enjoyed the M&Ms!). Just fill 'em up with 2 quarters, then a penny, then 2 quarters, then a penny, repeat, repeat, repeat... and you're ready for penny pressing all over the parks and even the resorts. Inexpensive souvenirs!
Some kids love pin-trading... others just love collecting pins... others get into the search for hidden Mickeys...
There is so much to do, and so many ways to have fun. I hope they really enjoy their trip!
