Mostly, he's for sensory processing issues. He does some guide work, balance work, and signal work. He'll tell me if I'm doing certain "stims" because there stims mean I'm either "stuck" or headed for sensory shutdown, and as long as I notice them I can react appropriately and if not postpone it, at least get somewhere where I can recover more easily. He stops at any street crossing, including crossing from a parking lot to the store and back. He find the car, entrances, exits, bathrooms, home, and follows routes to get to classes. He also does some deep pressure tasks, though I don't often need those in public and at home Gavroche is better at them. That said, every autism SD will probably do something different, because autism affects everyone differently.
Autism "service dogs" for kids are being popular, but 99% of the time it's done improperly - tie the kid to a dog and all your problems are solved, right?
I have seen it done well, but it's super rare. And there are very, very few places that will train an autism dog for an adult, because most places that "train" autism dogs don't actually train them, they just tie small children to them. But that could have a whole vent thread on its own