By the way, I do know basic Spanish, and would be willing to pay a reasonable fee to find this man's death certificate. Since it's a matter of clearing a title in order to purchase land in Croatia, I'm not the first person who's ever needed this service. Is there an agency that specializes in this, do you know?
I posted all the info I have in another reply, but here it is again:
Mate Ili? - born 1903 (exact date - not sure) Father's name is Stjepan Ili? He left Vis sometime between 1930 and 1935