i think your right Jeffro, there is no documentation that any of the items were ever stolen from anyone, in fact they were purchased and transported legally, long before UNESCO was even in existance. ( besides isn't there some type of statute of limitations on things like this ? ).
Also what they are not taking into account is that, in many of the old countries they have a very different idea from us, of what constitutes a valuable antiquity from musty old junk. they were probably happy to sell that old junk at the time. i think the artifacts or the profits from the sale of them, should go to the family of the deceased man or his heirs. and if that one brother doesn't want his share, perhaps he could donate it to the foodbank that he works at.