Just to add other Italians are Terrific stories ....
I have left my cross body bag in a restaurant bathroom in Narni. The owner turned it in immediately to the Poliza. Then took me the next day by the hand and directly to the office and would not leave until (finally) my bag was located. I've had complete strangers on a back road in Tuscany stop and help me get my car out of a ditch (yes, I didn't realize there was a drop off until my front wheel slid into it and the rear end of my car was up in the air about 4 feet). I even met the owner of a vineyard when I ended up lost in a tiny village outside Montalcino who got in her car and lead me down the narrow lanes and to her vineyard (and pulled out a very special Riserva Brunello for me as a gift for being tenacious at finding her vineyard).
I've had strangers hand me parking meter coins when I didn't have enough, and I've done the same for many American tourists who have no idea that the city meters take only coins. The sheep farmer down the road has helped me get my dog back out of the herd of sheep (where he thinks he is a lamb and wants to play with all the other little cute lambs). When my train ticket blew right out of my hand, the conductor smiled and told me no problem and helped me up with my bag.
I am 60 years old, stand out as a 6 foot tall American woman, and I travel all over Italy by myself by car and train. I have never felt the least bit nervous except in Naples and once in Rome at the train station when there was an obvious group of "distract and grab" pick pockets. Just don't call attention to yourself and walk with confidence!
If your dad needs a rest, I am willing to bet you have people coming to offer you help, a cold glass of water and the seat with the best breeze.
Hotels don't always have air conditioning -- it is a luxury here. If yours do not, ask that the bus stop at a large grocery store or hardware store and buy a fan for 16 Euros. Maybe one for each of you to keep you cool at night. Keep your window shutters closed during the heat of the day, and open them at night if you get a breeze. Rome is extremely hot these days. Most of Italy is predicted to have temperatures in the mid 90's to low 100's starting next week, so just make sure you always have water and a hand held fan. I carry a washcloth so I can dip it in any fountain I come across for a cold compress on the back of my neck, forehead and wrists. It really helps.
And one more tip: If your tour is not going to your preferred destination in the morning slot, consider arranging it on your own. By mid afternoon the streets are extremely hot, especially in older sections of the cities. See churches in the afternoons, and walk to destinations or outdoor attractions in the mornings. There is a good reason restaurants are closed typically between 4:00 and 7:00. It is just too hot to eat!
Have a fantastic time! Your father is a lucky man ---- he's going to have a fabulous trip!
Ciao!
Catherine