Found my answer on their website:
- Explore Mammoth Tours: Meet outside at either Canyon Lodge or Main Lodge supersigns. Tours leave the signs at 10:15 and last approximately 2.5 hours. Tours focus on how to get around Mammoth Mountain, answer your questions about the natural surroundings and history of our area as well as give pointers on fun activities to do while visiting Mammoth.
- Winter Naturalists Tours: Meet at the bottom of Stump Alley and Goldrush Express Lifts at 10:30. Tours last approximately 2 hours. These tours give you the inside line on the area, its volcanic background, help you identify the trees and animal prints you might run across and fill you in on information about the old mines that gave Mammoth Mountain its name.
That doesn't seem to be what your brother is looking for however. I'd look up something on google or send a PM out to someone on a ski forum.