Property under Coercion and undue influence

This is regarding a site allotted in Mysore to my father recently according to the supreme court judgement. HISTORY: My father (Party A) had been allotted a MUDA site in approximately 1991-1992 and was asked by the authority to pay the full amount to have the site registered in his name. He was not interested in the proposed property the reason being the allotted site was in a very remote area and not much developed during the time of allotment and he did not render the such amount, and MUDA did not allot the site. Thereafter after 20 years between 2012-2013, we approached a lawyer through one Mr. Nagraj (Party B) person available at all times near the MUDA office to approach and trap people with such as our case. He took all the original documents from us assuring to get the site allotted to us and had a contractual agreement between Party A and Party B, wherein, the contract expressly stating that he will bear the expenses of all legal proceedings, and once the site is allotted and disposed, both parties A and B will have equal share in the sale proceedings of the site. To explain in detail, if the site is allotted and market value is Rs. 10 lakhs and if Rs. 1 lakh is the legal proceeding expenses, etc., the remaining amount of Rs. 9 lakhs to be shared, i.e., 4.5 lakhs to be distributed to each party. In the meantime, Party B had approached the said advocate and did not remit the fees he asked for, and the case was quashed in the Karnataka high court after multiple attempts at proceedings. Of note, party B had previously won some of the similar cases and had pledged the alotted site documents(illegally acquired by him) with the advocate as fees, as the allotted persons had refused to comply with the contract, as the contract was in itself void initio void. Later, I, son of Party A happen to meet the advocate personally and requested him to proceed legally further without Party B's participation and tendered the required legal proceeding fees by ourselves. Then, the case was registered in supreme court and then after a prolonged period of time, it was adjudged and advised to us by the advocate to remit the allotted price amount along with interest till that date (approximately Rs. 1.8 lakhs) to the supreme court itself. At that moment, my father had no sufficient funds to remit the same and at the same time Party B knowing everything cunningly pitched into the picture along with one Mr. Pasha (Party C) who was ready to pay the amount of Rs. 1.8 Lakhs. At this juncture, there was again one more contractual agreement made between Party A and Party C with the agreement expressly stating that, "at the time of contractual agreement, the market value of the proposed site was just Rs. 7 lakhs and that the Party A is obliged to sell the property to Party C only and to nobody else," which is also an agreement ab initio void. Now at this point in time, the supreme court has awarded the site to Party A. Party B and party C are coercing with life-threatening warnings to the Party A (my father) to just sign the documents at the place and time they dictate and receive the amount in some thousand rupees or nothing claiming that Party A has contractual agreements with both Parties B and C, which are again legally ab initio void. Party A is under coercion and undue influence that he just wants to relieve of the situation and has agreed to do so, even without any remuneration with regard to the property allotted to him. Please guide me as to how to address this situation legally in the best interest of the Party A and his family and direct me, Party A's eldest son, as to the possibilities of getting a stay order on the property. FYI, Party A has two sons, age 43, that is me, the eldest, married, with one son; the youngest at age 33, and one daughter, age 40, married, with 2 children.