Ugh, that's frustrating :( They should accommodate him, not feed him the classic "not listening" line. You don't know how tired of that I've gotten in my lifetime! It's hard to "listen" when you have executive functioning deficits!

Has he been offered any Headphones? It may make all of the difference in the world for him.

There are 'Tracking' devices available which you can slip in their shoe(s) in case if they stray away from where they are supposed to be.
Get them a State I.D. that way their image is in the State Files as well as their information.

Ok so the school saying they don’t have funding for an aide this is public school correct? If I’m not mistaken (not an expert) but they can’t legally say that to you if it’s a public school funding can’t be a reason for them not getting your child an aide I’m going a similar experience and there doing accommodations and having a student help it’s been going well and fingers crossed but if not definitely fighting for an aide.. but let’s say they really just can’t do an aide for etc reason then finding an alternative way for him in the least restrictive environment possible if his running away defiantly talk about doing a evaluation or re eval for ot and have an fba do a evaluation to see if there’s a behavior plan that can be put in place. Again not an expert but we are in a similar situation

I am in Conway Arkansas.
And it’s not like he doesn’t understand it, as long as it’s 1 on 1 explaining.. and they know that too!