You keep them somewhere on a schedule or what ever so they don't disapear, (You also need to print out your last depreciation schedule and do the same with that). The taxpayer will need to keep track of both those pieces of information until they either sell the property or die. 

If they sell the house before they die, they will get the passive losses then (or possibly sooner if they end up with something creating passive income). I am pretty sure, if they die, the passive loss is lost, but the step up basis does happen in the property, and then you no longer have to worry about prior depreciation.