Who would administer this?
Right now, I'm fairly certain DS1 is ID. He does have an X-Linked Intellectual Disability however, very little is known about it and some of the milder cases can have iq's of 70 or slightly above. I know that some of time having a child/adult with ID is much easier to find assistance, grants and equipment.
Will his difficulty with receptive language and his inability to communicate skew the testing?
Re: IQ testing
It will. My dd just did the testing and was mostly uncooperative. She did well on the nonverbal portions of block sorting/patterns and puzzles but answered like three of the verbal questions before she said done and attempted to walk out of the room. Lol. It's incredibly hard to get a read on a preschool age kid. I'd probably wait until school age and then even take the results with a grain of salt as iq is a fluid number.