Legal Question in Credit and Debt Law in Pennsylvania

This makes no sense. The statute of limitations is the same for both borrower and co-signer in most instances. The place where the contract is made might dictate, even if the co-signer has moved unless the co-signer moved to a state with longer statute of limitations. However, the statute of limitations can be very complicated - there are also other factors (like tolling or borrowing) which may come into play where someone has moved to another state).

You don't set forth any relevant facts - where was the contract made? When? When was the debt last paid? Where does the borrower live now? What about the co-signer? Where can the lawsuit to collect the debt still be brought? Does either the borrower or co-signer have assets? Is the debt going to be collectible if a lawsuit is brought? And if the co-signer only is sued by the lender and pays, the co-signer can then turn around and sue the primary borrower to recover any amounts paid by the co-signer. If you are one of the parties (lender, borrower or co-signer) then you need to pay a lawyer to review the documents and circumstances.