I have a 5 year old with autism, non-verbal, super sensory sensitive. But he does PHENOMENALLY well at Disney. We've never taken a cruise, so this is my 2 cents on touring the parks.
His parent or grown up will know best, so if they're not already on here, point them in the right direction.
As others have said, using the
DAS and FP strategically is important. Get the card 1st thing when you go into the 1st park. Our first visit with him we didn't get the card until the 3rd day because I felt...I don't know...like I was taking advantage, like he shouldn't need it, maybe even embarrassed. We were worried about getting wheelchair tag, too, but thankfully the CM explained that it exists for just this reason. And what a life changer that was. He needs the personal space of the stroller when we're in the queues that are more enclosed or crowded. If your nephew doesn't usually use a stroller but you think he might benefit from it on this trip, BOB and similar large jogging strollers can be very comfortable for an average 5 year old and can be found second hand or borrowed. My son is very tall for his age and we just moved on to a chair made for bigger kids with special needs.
Does he elope? We use a safety harness made for big kids. They are hard to find for older kids but there's a lady in Canada who makes them. Awesome product. I can find the website if anyone is interested.
My son is a very picky eater so we always bring his food and have never had a problem doing so in a Disney restaurant.
Print out the park maps ahead of time so you're familiar with the escape routes. I cannot tell you how many times he needed to get out NOW and there was ANOTHER parade blocking us in.
Don't ever be afraid to as a CM for help.
Also, ignore the stares. Ignore the whispers from your own group.
He's loud? Who cares, the whole park is loud.
He's having a hard time? Guess what, someone else's typical 7 year old is having a tantrum right now because even the most typically developing kid can be on sensory overload in Disney!
It's going to be ok.
If other people in your group are embarrassed or affected by his behavior, they can walk away, and that's ok. No judgement in either direction.
Know who's turn it is to take him for a break, off the ride, back to swim, or whatever, so the situation can deescalate as fast as possible.
It seems daunting, but Disney is absolutely set up for families with special needs.
