Something of a catch 22 situation really.
Losing ones job means losing not only an income stream but also the resident visa.
Unless new employment is found, difficult at the moment, one has to leave the country.
What can be done ? I think the best course of action is to try to negotiate reduced loan payments from whatever country you are returning to. The banks will employ local collection agencies who will no doubt employ some scare tactics , you will be protected by government legislation in your own country as long as an effort, no matter how small , is made to repay what is owed.
As far as mortgages are concerned , positive equity is good, negative of course is the opposite. Losing the property to bank repossession is a possibility if it cannot be rented to cover costs. I’m sorry to say, but this happens worldwide.
As for parents , siblings etc being held hostage because of a relative,s ongoing debts, that is most unlikely in my opinion .