Initial Search For My Brother Who Probably Was Adopted

I am posting to this site as my first real attempt to find my brother. I know his original first name was William(Bill) and that he was born on October 25, 1956, at Augustana Hospital in Chicago, IL. All of my life, I was told by my mother that he died a few days after he was born. So I never questioned it. Then when my mother died in 1982(my father died in 1959) I found a journal of my grandmother. She was actually my step-grandmother and not a very nice lady. In this journal, she states that my brother was given up for adoption to St. Vincent dePaul Hon on 12/08/1956. I did not believe this at first due to this woman's history of lies and meaness. After thinking about it, I realized that since we were Catholics, if the baby had died, he would of had to be buried and my mother and I never visited a grave. When my father died, we visited his grave daily for six months and then frequently after that. This lead me to believe the adoption story might be true. So here I am, the sister who has no legal right to the closed adoption records and no living family members to confirm or deny. I actually do not know for sure the last name that would have been on my brother's birth certificate, possiibly Villano or Crowley or ? If anyone who was adopted, looking for birth family member and was born on 10/25/56, please contact me.