There seems to be some confusion if his name was Gershon or Gershom. Indeed, according to this document I posted here: https://www.geni.com/documents/view/6000000038788047888?doc_id=6000... top line there were two brothers one called Gershom and one called Gershon.
I have various other sources that the father of Rabbi Shimshon Katz was GershoM. GershoM had a brother GershoN.