Hi Nysnanna
The assessor will usually want to speak direct to the claimant for them to assess the claimant, we do hear on the forum that when an assessment gets difficult then the assessor may ask their support worker for information or they may terminate the assessment.
The question I would ask before going to the assessment is, has support documents been sent in to support his autism claim, if it has then it should give the assessor a heads up about the likely outcome of the assessment and any protential problems.
Have a look at out guides if you have not already done so
www.benefitsandwork.co.uk/help-for-claimants/esa1 Gary