Hello Dina.
I have just located my half-sister's siblings from her father's side.
If you are able to somehow obtain your father's birth last name, and maybe the town where he was born, then go to
www.infobel.com and put in those two things. In our case putting in the last name and the town here her father was from came up with 6 names.
We had a form letter typed up, had it translated into Italian and mailed it to these 6 people.
We were lucky, because one of those names did turn out to be her brother.
If you are able to find out this information and have someone translate the form letter into Italian, and put in all the information you can find on your father: his birth name, maybe his parents names, his birth date, names of his siblings, etc ---- anything useful you can find.
If they don't respond -- don't be surprised -- that sometimes happens.
Good luck to you.
Angie