After a visit to the mechanic for a tires swap, the tires came off on the road.?

We took my uncle's car to a mechanic to get the tires swap. Upon inspection of the car, the mechanic estimated the charge to be around $200 because the bolts for the tires were made for Hondas, not Mitsubishi's (my uncle's car). We had to purchase the bolts from the shop. The mechanic ured us that his price was just because he's really just helping us out and since my uncle will be driving for 6 hrs. to get home, all he is concerned about is my uncle's safety. What he suggested was to be the safest. Well, after 2 hrs. on the road, some of the tires came off. My uncle had to put them back on with the menial tools he had and with the help of a flash light in the middle of the night on the freeway. In addition to that, the wobbling motion of the tires damaged the sides of the car. Now we are looking at either negotiating a settlement with the shop, or suing them. How do we go about doing either of those?