Hello here go my 2 cents:
Elpanada! Your answer sounds a bit drastic - I think it is probably natural for parents in far away countries to worry about such things. Particularly when there are geographic, cultural differences, language barriers? I know it would be a concern of my parents!!!
An argentine friend of my mothers married to a dutch man for over 10 years got scammed out of the house she had bought with her Argentine inheritance in their divorce (the house was in Holland) ...now she is living on what she can... Of course this is an extreme case and so on, I believe their concern may be valid.
Prenups are not valid in Argentina, I believe, as there are "herederos forzosos/ forced heirs"- the spouse is entitled to 50% of everything you have both made during the years of mariage. Everything you had before, if it has been notarized is yours and cannot be touched , everything you inherit and has been notarized I have been told is yours and cannot be touched.
I believe that to be the law in Argentina- but if there are any argentine lawyers around do bring more precisions.
I am sure the info wont be necessary but if it helps put your parents at rest, then so be it...