Seeking information about Robert Alicea

My son and Grandson are asking about family. Robert Alicea from Philadelphia was my son's birth father. He was born on 21 August 1954 and was buried in Greenmount Cemetery on 26 January 1978. We do not know his parent's names but believe they immigrated from Puerto Rico. They lived near CAMBRIA and REESE Streets in Philadelphia where Robert was born. Was Robert mentioned in a will, or probate record? Did he have a   criminal record? Was he sent to prison?  My son would love to find extended family. Please can you help us? Thank you. If you can suggest anything else we can try, please let us know.