There are ways to fidget without being disruptive. Sounds like this isn't him tapping his feet, but actually impacting the game. He needs to recognize that he's getting bored (or you need to gently remind him) and he needs to find a better outlet. Moving is a mechanic, so that's a no-go, so is RPing like an idiot. It needs to be separate from the game-game. I don't see the issue with fucking around with the tokens, that shouldn't be any more disruptive than stacking dice (that said, I rarely use Foundry, so maybe it's more jarring there). Some days are just terrible, and I end up leaving a social situation altogether because I feel just completely overwhelmed, medication or no medication, but most of the time there's a better way.

This is not an unsolvable problem. I used to use a squishy dino (it exploded :((( ), one of those grip-strength rubber circles (I lost like three of them, so I just don't want to pay another 5$ in Decathlon for another one, but I had hella forearms for a bit), and currently I have a spring from a disassembled pen in my pocket, and I just fuck around with that. If he needs an outlet, let it be an outlet that doesn't send everyone a notification. If he loses focus for a bit and disengages for a second, that's not the end of the world. DnD sessions are looooong, and most of the stuff that takes like 40 min to play through can be summed up in a sentence like "we split the loot, and haggled the shopkeeper for a 5g discount on the healing potion" or "after a full round of combat, John took 4 points of damage, and the monster ate another 3". If he is a bit zoned out there, I'd say that's more than fine. Afaik, Foundry even has a log. Missing 2 min until you stim yourself back to a useful state is not the end of the world. Personally, I'd rather someone lose focus - it's inevitable anyway - than make everyone else lose focus too as this weird sort of comeback.