Care worker accident query

Hi, this is regarding general advice on a matter related to an injury happening as a result of a road accident. Suppose your care taker who was employed locally , a year or so ago, who's looking after elderly person at a residence 24x7, and occasionally steps out in the day for small errands or personal break or rest, etc at random points of time, and on one such trip meets with an accident, and some vehicle hits them. Who would be the primary liable for compensation in that case ? Wouldn't it be the person driving the vehicle that caused the accident ? Suppose the accident leads to long running injuries etc. and it means the person is not able to work, what are the factors to be considered on the liability of that person. And whoever the person liable, what is the maximum extent of liability.