Local boy passes away after battle with terminal brain cancer Sheriff's Law Enforcement Association of McLennan County and last updated 2021-02-07 11:34:57-05 A local boy has passed away after a battle with terminal brain cancer. Jon Mathew Graefser passed away Saturday after fighting medulloblastoma, a terminal brain cancer, for the second time in five years, according to a "Prayers for Jon" Facebook page. The Sheriff's Law Enforcement Association of McLennan County posted a tribute to the young boy on Sunday saying his mother was a corporal in the jail division before having to leave the sheriff's office to take care of Jon.