Dear Sir/ Ma'am,
Since it is clear by the facts that the builder had ulterior motives of gaining monetary benefits by providing compulsory services other than the contract, it is advisable for your parents to hire an advocate or a legal representative who can represent them in court. Such in-court representative shall have no issue with the local language of the place.
You must hire a lawyer who has a background expertise in cases like these and is competent to represent your case at the court.
It is further suggested that you can send a legal notice to the builder warning him to comply to the provisions of the Contract and not practice beyond it for monetary gains. Also, you can file for the damages for the mental harassment your parents had to go through.
Case of translation
The Code of Civil Procedure, 1908, was amended by the Parliament by Act No. 2 of 1951. This amending Act extended the Code of Civil Procedure 1908 to all part-B States including the State of Madhya Bharat. The amending Act came into force on 1st April, 1951. and thereafter the Code of Civil Procedure, 1908, became operative in Madhya Bharat and the Madhya Bharat "Indian Civil Procedure Code Adaptation Act, 1949. (Act No. 70 of 1949) stood repealed. The material provision is Section 137 of the Code of Civil Procedure, 1908 is as follows:
"(1) The language which, on the commencement of this Code, is the language of any Court subordinate to a High Court shall continue to be the language of such subordinate Court until the State Government otherwise directs.
(2) The State Government may declare what shall be the language of any such Court and in what character applications to and proceedings in such Courts shall be written.
(3) Where this Code requires or allows anything other than the recording of evidence to be done in writing in any such Court, such writing may be In English; but if any party or his pleader is unacquainted with English a translation into the language of the Court shall, at Ms request be supplied to him; and the Court shall make such order as it thinks fit in respect of the payment of the costs of such translation".