Well she is not critiquing his "artwork", she is concerned about his self awareness..
It is not a big deal, just something to consider if your son is aware of details.. Not just the big picture in his world.
It is just a small sign of an immaturity, but nothing to worry about..
Make sure you all talk about the little things.
Is your son aware of what the light signal colors mean?
Does he notice you use turn signals? That it takes an action to communicate, but does not have to be with words?
Do you all talk about feelings? Frustration vs angry? Embarrassed vs feelings being hurt?
Is he aware of his senses? Have you ever blind folded him and let him try to walk around a room? Feed him different foods to see if he can guess what they are by just smell or taste?
Has he tried putting cotton balls in his ears while you whisper words to him and have him try to guess what you are saying? By just using his eyes?
Have you tried to show how much he can hold in his arms and walk without dropping things?
Can he walk one foot right in front of each foot, how about backwards? Can he hop on one foot and then another while on a drawn line?
All of these activities will remind him of his features.. Not just what his brain has been taught.. can do, but what he can do just naturally.. This is very important for his "self awareness".
Eventually it will change his "picture" of himself.