This is really something you will need to discuss with the school and their accessibility/SEN team I would think.
If he's doing a course where work experience is integral as above it might be harder to avoid, although from the sound of things he isn't. If just doing A-levels or something I can't see why he would need to do work experience - I certainly didn't after the compulsory year 10 work experience we had.
If work experience is required for the course, you could discuss with them any options that might ameliorate the situation, for example seeing if he could do it at the school in some capacity so it's in a familiar environment with familiar faces etc. Obviously some kinds of work experience in a school may not be suitable due to safeguarding requirements, but there may be something they could find if necessary that could fit the bill.