At most, they'll get a couple of years: https://www.leamingtoncourier.co.uk/news/man-arrested-in-connection-with-m6-collision-in-warwickshire-1-8377899

He hasn't been tried yet, maybe he wont be? But unless under the influence of drink or drugs I doubt he'll get a custodial sentence.

My granddad was killed on a zebra crossing by a youngster speeding. (The police couldn't replicate the speed!) In court it was virtually made out to be the old man's fault for using a (lit) crossing at night! The judge even passed comment that he was well passed normal life expectancy anyway.