If there are 6 of you, including your son, you shouldn't have any problems at all. You should all be allowed to board in the same place as your son, so your party can stay together. In fact, most of the attractions now have mainstreamed queuing.
This means that you'll be going the same route as everybody else, but just going to a different boarding place, or the special seating area at shows, towards the end of the line. If you want to know where to go for each attraction, you can pick up a guide for guests with disabilities at Guest Relations. However, it's normally clearly signed, and there are always CMs about to guide you if you get stuck - I know that kids won't always wait patiently for the grown-ups to read the guidebook, when there's fun to be had (yup, I was that kid once too
)!
You might not all be able to fit in to some of the wheelchair viewing areas, but if you arrive early, you could probably get a space right next to the viewing area, so your group still stays together. Besides, you're going at a quiet time of year, so hopefully the wheelchair viewing areas won't be too crowded (we went earlier this month, and we always had a fair bit of room - at AK there were only 3 or 4 groups in the first viewing area on the parade route!).
You might also find that for some shows, such as Fantasmic, some people will have to sit in the row in front. This is roped off and looked after by CMs, just the same as the wheelchair viewing area, so you'll still be able to see the show together. There's a small bench between each of the wheelchair spaces at these shows, but some will only fit 3 or 4 people, and that includes the party next to you.
Don't worry, everything should be a piece of cake!
