When Sandusky retired from PSU he was only 55. He had been widely believed to be the heir apparent. He left for a reason.
Total speculation on my part but it seems as if the meeting at Paterno’s home (after the grad student’s report) was to arrange a cover up.
Grad student’s report didn’t happen till ‘02. First investigation was at the behest of a parent in ‘98, Sandusky retired shortly after that after Paterno denied him the head coach job.