Could he be a companion to an older person or a more severely disabled child? Sounds like he's pretty handy and pleasant to be around. Maybe an aide at an afterschool program for handicapped children?
One of the women I worked with has a handicapped daughter that went to community college after high school and qualified for working with pre-school children and loves that.
Here's a California nonprofit that trains local handicapped people to work with animals:
http://abclocal.go.com/kgo/story?sec...cus&id=4585339
Maybe the two of you could form a pet-sitting/house-sitting company?
I use to look through the yellow pages phone book, see all the classifications/companies/ideas out there for ideas of my own of things that might interest me (also looked through the encyclopedia like kids do :-) Maybe the community college offers career testing or has some ideas? Even if he can't read well he might be able to work in a library; shelving books and organizing/fixing equipment and materials. There's quite a few behind the scenes jobs in schools and libraries; maybe he could be a school cafeteria worker; a little loud but not too many people?