Understanding without responding verbally

For typical children, understanding of any verbal instruction or even of a situation is conveyed usally by a verbal response or a nod of the head. Not so for a non verbal child like Adi. I know that he understands most of what is being said - or does he ?

There are 2 ways to find out -

• Ask him if he understands what is being said. Usually this fails. He does not respond.
• Convey instructions ending with an action that he needs to perform if he has understood what has been said. Example - Adi - let us go for a swim. Change your clothes and wear shoes. He will respond by trying to change into the appropriate attire as best as he can.

In Indian households, especially uring the summer vacaton, there are many commands which we  will/ are trying to give around the kitchen and the house - to get him to do something involving physical motion - should he understand what is being said.

P.S. Do autistic kids really love pizza and grilled KFC chicken so much?