gible to be the statutory auditor of the holding company if the firm was earlier the statutory auditor of a wholly owned subsidiary and has completed its term to be the statutory auditor of the subsy?

The Companies Act does not restrict the auditor of subsidiary company from being the auditor of the holding company. 

But what if the auditor of the subsidiary company has ceased its audit tenure and would now be rotated? Would being ineligible to be the auditors for the subsy make it ineligible to be the auditors of the holding company?

If the ineligibility of the auditor is due to the various factors as mentioned in Section 141 of Companies Act, 2013, then he cannot be rotated and ineligibility in subsidiary would also render him ineligible to become auditor in holding company as well.