What they are doing. Getting on with life and accepting that they are a family with a missing member. They're not the only ones, there are many such families.
Never an easy option for the families of missing people I would imagine. Even those who are not the focus of abusive internet interventions and whose cases were conducted competently and at length by the police at the time, leaving no stone unturned and no further avenues to be pursued.
Cases of missing children are never closed as Madeleine's apparently was. Within a year of any other child being reported missing has a file marked as being irrelevant to the inquiry been set up to which ALL incoming information good, bad or indifferent was relegated?
Can you name one instance?
If you can't I suggest that Madeleine having been singularly maltreated by the authorities deserves the unfinished business of her case to be dealt with as long as it is supported by evidence. As is the norm for cases of missing children for whom all the stops have been pulled out which must at least give a small measure of comfort to their grieving families.