Crowd view of the massive crash at the British Grand Prix

Probably not. That one was a matter of rapid deceleration and a freak accident with the suspension:

When Sid Watkins arrived at Maggiore, he conferred with the doctors who had been treating Senna. They had ordered an immediate brain scan. It merely confirmed that Senna had no chance of surviving the accident. Watkins was told Senna had multiple fractures of the base of the skull where his head had smashed into the carbon-fibre headrest of the monocoque. What had likely happened was that the right front wheel had shot up after impact like a catapult and violated the cockpit area where Senna was sitting. It impacted the right frontal area of his helmet, and the violence of the wheel’s impact pushed his head back against the headrest, causing the fatal skull fractures. A piece of upright attached to the wheel had partially penetrated his helmet and made a big indent in his forehead. In addition, it appeared that a jagged piece of the upright assembly had penetrated the helmet visor just above his right eye. Any one of the three injuries would probably have killed him. The combination of them all made it certain.

I don't think any of those could have been stopped with the Halo. The HANS device maybe could have saved him from the deceleration, but all three were too much to survive

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