It is common for celebrities or other high profile people with private planes to have the FAA block their flight data. It is a simple form.
https://www.faa.gov/pilots/ladd
He should do this in addition to any other steps he feels are necessary.
Maybe already did. Not available at flightaware...
N628TS - FALCON LANDING LLC (HAWTHORNE CA)
This aircraft (N628TS) is not available for public tracking per request from the owner/operator.