iTouch-SPED

I have a severely disabled student in my music class. Great kid, very helpful, IQ around 50-60.

He has been using my iTouch and it seems to be working.

I would like him to be able to:

1. Do basic categories. Can he find a picture of a trombone by going to photos-instruments-trombone. Are there apps/games for categorizing?
2. Loud/soft, hi/low, fast/slow. All the basic music skills.
3. Any music related games, flashcards, etc...
4. Can we create/compose ----real simple and structured? Apps?

Any lists of apps or strategies would be great. Free is best.