Presumably they’ll lose the home they can’t afford on their own. The banks will learn not to grant mortgage loans based on theoretical future income without an employment contract.

The options I see are as follows: 1) all residents are responsible for paying rent/mortgage and can be evicted for nonpayment 2) only vulnerable residents are protected from eviction 3) property owners are responsible for paying their mortgages and can have their property repossessed for nonpayment 4) mortgage issuers have to eat it if owners can’t get rent from tenants.

Worst case in 1: people end up homeless. Worst case in 2: landlords stop renting to vulnerable people or charge them extra as insurance against future nonpayment. Worst case in 3: landlords who took out loans for properties they don’t live in based on future rent income they now can’t collect have those properties repossessed. Worst case in 4: I guess the banks could fail, but more likely they suffer some proportionally minor losses and then get more selective about granting mortgage loans dependent on rental income.

Of these, it looks like numbers three and four have consequences much less damaging to the most vulnerable people in society.