Unable to repay debt- urgent solution req

Hi,

PLease Suggest the Solution for my Friends Father.

Because of some Circumstances My friends father took LARGE AMOUNT money from individuals at higher intrests rates i.e., 5rs/month. he knows that intrest is high but he does not any choice. He paid intrests for Years. (Taking money from others and paying.) And those persons used him very well so that they will get atleast 50% intrest rate per annum if they give money to him.,

Now he is not able to pay the money as his salary is not enough to repay them.

ANd recently they are forcing, scolding & giving warnings to pay acutual sum alog with intrest.

Once we cross check how much he took and how much he paid through intrest allover years, it was found that he almost (somecases more also) paid the acual amount with nominal intrest ( intrest charged by banks).

is there any way to get him out from this situation. 

please note that they earned money only by giving money to my friends father. they(who used My friends father) dont have any employment to proove their income from intrests..(they wont pay any TAX)

Could you please Help HIm out.and what are the legal procedures to follow.

He can Repay in installments if the sum payble is justified by court.

recently Heard about  INABILITY TO PAY THE DEBT.  what is it.? IS it applicable to individual.

Could you Please Suggest the Solutions ASAP