Hi Lisa!
Your "Disney mad brother" is a guy after my own heart. I am a huge fan of the Backstage Tours & love seeing how all the magic comes together. I think that safety may play a part in the reason there is a minimum age requirement. I've never felt like I was in any danger on any of the tours but you do visit some of the actual work areas & have to follow safety guidelines when in those areas. Depending on the tour your take, you could visit Holiday Services ( a huge warehouse), Central Shops (where they may be working on attraction vehicles) or the horticulture department.
They also don't want to spoil the magic. The glitz and glamor is "on stage" and Cast Members are getting ready in the backstage areas. For some guests, seeing a character in the utilidors before they are fully ready could ruin it for you. Guests have to be able to handle that if it happens because they don't stop work just because a tour group is coming through.
Some tours may not hold the attention of guests under 16. A lot of the tours involve walking around, looking & listening but not so much hands on or going on rides. I've seen some younger guests on the tours look like their parents made them come & they weren't very excited or interested.
There are some
tours & special experiences your brother may enjoy that have a lower minimum age:
* Dining with an Imagineer
* Wild Africa Trek
* Wild By Design
* Walt Disney: Marceline to Magic Kingdom Tour
* Disney's The Magic Behind Our Steam Trains Tour
* Behind the Seeds at Epcot
* Dolphins in Depth
* Epcot DiveQuest
* Seas Aqua Tour
Tell your brother to keep on loving Disney & start planning another trip after his birthday. Wishing you minnie magical memories :-) Allison