Building contractor issue

A contractor was hired to build a residential property in Mar 2022. As per the agreement, he had agreed to complete the project by Sep 2022. However, in Sep the project was not completed and the contractor said there would be some additional charges for the few modifications done in the building ( few of which was requested by the owner and others that happened due to incorrect construction by the contractor). A second agreement was signed with the additional amount quoted as agreed by both parties. The contractor took the first payment after the second agreement and stopped taking owner's calls. After several months of follow up and expiry of the second agreement, he again quoted additional cost for work to be completed. Since he had already caused a huge delay and now demands more money, the owner was not willing to continue the construction with him. However, the contractor is threatening that work can be continued only if his money is settled. The owner asked for proper bills and explanation for the work completed upto this point. But the contractor is not providing it. Even when this was taken to the police station, they asked for bills which the contractor is not providing and claims he would face it in court. The owner is a retired senior citizen. The delay in project completion has caused expiry of the building plan, increased cost of materials and health issues in the elderly couple. They fear if this moves to court, it will further delay the work progress and cause multiple court visits which their health may not be able to accommodate. Is there any way out of this? Kindly suggest