Ahoy, Maria!
Thanks for visiting the Disney Parks Moms Panel with your question, I'm happy to help! No need for concern, Maria - one of the best things about a Disney Cruise Line vacation is their commitment to make every experience for EVERY guest memorable and accessible.
I'm so happy to hear about your son's love for people and all the Disney Characters - we have that in common! He'll certainly have plenty of opportunities to interact with many of his favorite characters while onboard. Each day you'll receive a Personal Navigator (a detailed schedule with times/locations of activities) that will give you information about Character Meet-and-Greets. It's not uncommon to have the Atrium Lobby full of characters for a gathering - it's a sight to see!
You can find information about how Disney Cruise Line accommodates guests with disabilities
here. If you'd like to speak with someone regarding your son's specific disabilities, you can call the Special Services department at (407)566-3602. They are happy to help each and every guest, and would love to talk to you about your specific needs!
I hope this information is helpful, and eases your concern. Your son is sure to have a magical vacation aboard a Disney Cruise. I hope you and your family have a wonderful time cruising with Captain Mickey!
Bon Voyage! - Diane W.