Hi DiamondDoris,
I'm on the autism spectrum and might be able to help explain some of his behaviour, assuming he does turn out to be diagnosed with it.
You say that at school pickup time he going floppy several times, lay down in muddy grass, licked pavement, ate sycamores leaves and tried to run off several times?
I wonder if it's because of sensory overload at the end of a long day? How is his behaviour mid morning on a normal day, rather than first or last thing?
For me, it would be like this...I get up in the morning and cope with the pain of getting ready (washing, teeth, hair, putting on clothes etc), then I go into a wall of noise outside (traffic, birds, people) and get to school where there is an avalanche of sensory stuff (people, eye contact, social stuff happening, noise, dust, rules to follow). I go into a classroom where there's more overwhelming stuff (computers whirring, overhead lights flickering, teachers and pupils voices mingling into one nightmare noise), and I cope all day long but I'm getting more and more and more tired and scared and stressed and I want to hide under something or do something really repetitive so I can focus on that and not the pain any more.
I get to the end of the day and out into the chaos of everyone leaving - all those voices, all that saying goodbye and people jostling each other, and I'm so tired now that I want to crawl under something and never come out again.
But instead I just collapse down and focus on what I see in front of me - the pavement - how does it taste? Can I focus on that rather than the scary noise and me feeling SO tired and so scared? Can I taste this leaf to see if it helps take my mind off things? Can I run away from the noise and the scariness?
Sometimes it's just us trying our very best to cope with the uncopeable.
What might help is a different school routine or a different way to pick him up from school -something very very quiet and slow so he has a chance to just 'be' and get home and chill out.
For me, a wrist strap hurts like hell. His response may be different.
Might help, might not...Just thoughts really.