The Banks/NBFCs might request family members to pay the dues, but they cannot force the family members to pay the dues, unless a family member signed some sort of agreement to pay dues on someone's behalf, but I am not sure if such agreement exists.
Other things these financials institutions I guess can do is recover dues from bank account balance (if such clause is part of the CC / Loan agreement) or dilute FD (in case of secured cards).
They might take possession of the assets purchased from the loan amount (in case of vehicle loans , house loans)