Margaret , I don't have experience with older cats ; but as you say this cat seems in pai when petted , i'm almost sure that she has some skin-illness ! Or those knots are bothering here !!
If in any way , you could contact this people , I would advise them to see a vet as soon as possible !! let us know how this devellopes !! btw , how old is "old" ??

your own kitty's are adorable !!! that calico looks very much like my own Maya !!! so it is a girl too then ?!