Sec. 4. (a) This section applies to:
(1) a joint debtor; and
(2) the representatives of a joint debtor;
in whose favor the statute of limitations has operated.
(b) A person described under subsection (a) is not liable to:
(1) a joint debtor or surety; or
(2) the representatives of a joint debtor or surety;
upon payment by the joint debtor or surety, or the representative of the debt, or any part of it.