Looking to see if anyone has info about Maurice Sullivan (b 1810?) and Mary Lawler (b 1815?). I believe they were born in County Kerry based on their son's death certificate. They moved to St. Louis Missouri sometime before his birth (1855).
John may have had siblings named based on census data:
Maurice Sullivan (b 1845)
Bridget Sullivan (b 1844)
Julia Sullivan (b 1849)
I do not know if they were born in Ireland or United States.