If the assets have not yet been legally distributed (probated), then the estate, by its administrator or executor, can file a lawsuit against the family members for the return of the objects; the lawsuit would essentially allege theft (unauthorized taking of another's--in this case, the estate's) belongings. In the lawsuit, the estate could seek either or some combination of the return of the specific belongings or their economic value. If the assets had been distributed, then whichever person would have received those belongings--presumably the wife--could personally sue those family members in the same way.