Awkward. TinyTractor is autistic, he's 17, so not a dissimilar agegroup. You either have to ride the situation out, or pre-plan properly. The club and stewards are very good, but if they don't know, they can't help.
He used to wear a lanyard everywhere, but doesn't like to now, especially in places he feels more comfortable. But he does keep it in his pocket and puts it on if he's getting nervous. He doesn't have tourettes, but he has a foul mouth on him and swears all the time at home, but controls it in public.
We have a carefully chosen location so he doesn't feel intimidated, all the stewards around us are aware and supportive. You can't expect every steward to treat every swearing teenager as if they have a hidden disability though. There has to be an degree of parental responsibility too. We don't go to away games where there isn't somewhere suitable we can sit. But we have to plan it in advance. Routine helps keep stress levels down and reduces the risk of getting angry or upset. So we get in the ground early, go to the loo, get snacks for half time etc, and then sit down. The stewards all see us and chat. Any new ones soon pick up that he has autism by the way he interacts with the other stewards.
We had a similar issue in our local Tesco Express a couple of weeks ago. The self serve checkout wasn't working, he started getting frustrated, and the woman on the checkout asked him to stop shouting, he was scaring the other customers. I told her he was autistic but she wouldn't have it. He started having a meltdown. So we left, I took him home, and went back and spoke to the manager. The woman no longer works at our local Tesco.
But you have to deal with it and get some sort or resolution or something, otherwise he will, like you said, not want to go again.
Feel free to DM me if you want.