The main problem is that Pier Giorgio would NEVER be called only "Pier" by anyone who knew him. So why do it? It's a bit disrespectful to him and to his memory to insist on calling him something that isn't right! A lot of people don't realize that his middle name is MIchelangelo. His first name is "Pier Giorgio." If it ever got shortened, they called him "Giorgio" -- not "Pier." If you read the book of his letters, you will see that he would often use "Giorgio." Even when he wrote in German, he signed his name "Georg" (German for "George," of course.)
Pier Giorgio also had several nicknames. When he was a little boy, he gave himself the nickname, "Dodo." As an adult, the nickname he probably used most for himself was "Robespierre" -- a name originating from the French Revolution. Although it had sinister connotations, Pier Giorgio used the name lightheartedly among his closest friends and gave them nicknames as well. When he became a Third Order Dominican, he took a religious name which he often used. It was
. (On a separate note, it has occasionally been reported that Pier Giorgio discerned a religious vocation and joined the Dominican Fathers. This is not true. He was only a lay member of the Dominicans.)
Blessed Pier Giorgio Michelangelo Frassati is a very long name. So, you can use, "Blessed Giorgio," "Blessed Pier Giorgio," or "Blessed Frassati," or "Blessed Giorgio Frassati," but never ever "Blessed Pier." Capisce?!