General power of attorney

Procedure reqires only the presence of the defendant (or his authorised agent) and/or the duly authorised advocate. There are no documents to be signed. 

It is ideal that your father engages an advocate and conduct the case with his assistance and guidance.

Besides getting a power of attorney deed executed in your favor for the purpose of court case, an affidavit is to be filed by you before court seeking permission to be appointed as your father's representative through the POA deed and your advocate can file a petition under order III Rule 2 CPC seeking court permission to permit you to represent him for the reasons stated therein. 

You can represent your father in the case/ suit on the strength of PoA.