As a stripper, I used to dance for a variety of differently abled people. While I'm aware that autism (especially someone who isn't high-functioning, if that's the case) is different, I'd venture to suggest that if this young man can handle himself appropriately in a strip club environment, some understanding and patient dancers might be a good way to slowly introduce him to sexual scenarios and help him to explore his own sexuality without the pressure of actual intercourse. If he enjoys lapdances and all goes well, then an escort sounds like a good next step. Like the poster before me suggested, sex might be difficult for him if he's really never had any previous experience. It's a process for everyone, and I'd imagine an autistic person would need to take things slower than most.
That said, I'd be happy to work with the client in question, if he's near the LA area.