I can also see someone whistle-blowing in good faith, getting harassed by ex-coworkers/managers or the court of public opinion, and just getting overwhelmed by the negative attention and feeling bad for the betrayal and killing themselves.
I can't really see a company faking the suicide of someone that already whistleblew and got national attention. That seems like a great way to exacerbate a problem that, if you leave it alone, probably won't be made worse by your leaving it alone. Like, what, a Boeing executive hired an assassin off the dark web with the click of a button to kill someone that already did the thing he was going to do? Executives can make some pretty poor decisions, so I'm not going to say it's impossible, but it would be a pretty wild mistake to make.
Seems extremely unlikely that they would decide to kill themselves after 32 years at Boeing and deciding to blow the whistle.
"Barnett, who spent decades working for Boeing at its plants in Everett, Wash., and North Charleston, S.C., had repeatedly alleged that Boeing's manufacturing practices had declined — and that rather than improve them, he added, managers had pressured workers not to document potential defects and problems. "