It's been the recommended method from the rational suicide movement for at least two decades. When people don't have the option of physician-assisted via medication, know that their continuing life is likely to be painful and undignified, don't want to leave a horrible mess for someone else to clean up, and don't want the risk of surviving an overdose, helium is the best option. Our brains don't have suffocation sensors for helium gas (we do for carbon dioxide, carbon monoxide, and nitrogen gas) so it's definitely not a cry for help attempt method. Helium hoods will kill you dead, quickly and painlessly. Once in a while, a teenager or two will decide they want to have a couple hours of squeaky voice, buy a party tank and crawl into a tent with it. It's their last mistake.
National Suicide Prevention Hotline: 1-800-273-8255
For Deaf/Hard of hearing: https://suicidepreventionlifeline.org/help-yourself/for-deaf-hard-of-hearing/ (Chat line and TTY number)
Mr. Smith, for all of his conservative attitude, seems to have been a meticulous and organized person. I may disagree with his politics, but what data there is sounds like someone at end of life, wanting to be finished, clearing his conscience and organizing his affairs. (Which does not entirely eliminate the idea that a hit could have replicated it, but despite spending the last nine months in the low probability version of our universe, I'm still gonna call horses when I hear hoofbeats. And the Russians do elaborate and baroque hits, but this isn't their style. It's not baroque enough, not obscure enough, and too practical.)
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