Drivers in Italy

I used MyDayTrip to go from Rome to Orvieto with stops at Sacro Bosco and Civita di Banoregio. The driver was prompt and courteous, and the car was comfortable and clean.

https://mydaytrip.com/

Does your friend realize those 3 transfers add up to about 600 miles? That will be unbelievably expensive for hiring a series of private drivers in Italy and it will take more time than the trains to reach your destinations. Unless you want to take out a home equity loan (!)you might want to take trains which could cost as little as $57 each of you for all three legs of the itinerary if you buy them online now.
www.trenitalia.com

If you are an experienced train traveler why can't you help the 77 y.o. person navigate the trains while you travel together? Unless that person has serious mobility issues, it would be much cheaper, faster and more comfortable to travel by train, then take a taxi between the train stations and the hotels. The distances between those cities are such that the drivers' cost would be several thousands of dollars vs. about $150 per person (all inclusive) by train.

And you will likely have to hire three separate drivers unless you want to pay for their lodging and meals in addition to the fares of several thousands of euros.

The link provided by BB, calculates a cost of ~$1800 for the proposed trip. That would likely be in a Corolla or VW Jetta size car. A more spacious/comfortable car will be more.

Any recommendations?

Give thought to using trains

I would consider using a train for long distance, then private driver for shorter trips. Really, all that means is Rome to some convenient station on the main line near Assisi by train, A driver to and from Assisi back to the station, then train to Milan, and then train to Turin.

A private driver between major cities really makes no sense unless a person has severe disabilities, or an extreme excess of cash.

If you navigate the trains, you should be fine.