This is a tricky question, let me try
The one option was to take priority from Korean application and immediately filing a conventional application in India because client was in hurry. However, it would take 18 month time for publication then examination and prosecution. it is ruled out.
Now client wishes to file through PCT, means he might want to take the benifit of good ISR and examination (favourable examination report). Definetly, this will help him in getting through the local examination with more confident.
As per the law you can inter national phase in India till 31 month from the Priority Date. If client is not interested in claiming priority, it will not change normal course filing.
The following documents have to be furnished either along with the Application:
(i) Assignment deed where the applicant is not the inventor,
(ii) Declaration of inventorship by the Applicant,
(iii) Statement and undertaking regarding status of corresponding Applications in other countries every six months,
(iv) Power of Attorney to agent (duly stamped),
(v) Copy of PCT/IB/304 or Priority document. If priority document is in any language other than English an English translation of the same along with certification in support of the same.
(vi) International Search Report
(vii) International Preliminary Examination Report, if any.
However, to get early patent in India, client can opt for expressed examination option. Client application is already published and supported by ISR and IPER; this will help the case at prosecution stage.
Please note that this is my generalized view and should not be considered as an opinion.
Dear colleagues correct me, whereever I am wrong