@cgr "muh proof" god you're such a denialist, , why are you so desperate to push the belief that he survived, can't you handle a sad story?
But if you want some of backing to what I said here's some.
Do you realize that tsunbaka's tone is way different than the one in this work? You have fucking cyborgs in tsunbaka, this one is grounded in reality with nothing over the top, given how this oneshot stuck to that tone until the end, boon falling from such a high place will mean his death is pretty obvious . If you even check the last panel, you see boon naked and flying up, which is pretty much the symbolization of his spirit ascending, how do you interpret this to deny he died, I have no fucking idea. Do you think he finally learned to fly or something? lol.
It makes way more sense for this to be a separate story with no relation to tsunbaka other than sharing boon as MC given how much shit is missing from tsunbaka. Where is tsun? boon in tsunbaka is fat and tall, while here he's smaller. Their personalities are totally different too, with tsunbaka's boon being like caretaker for tsun since early age, a centered guy who knows what he wants, a guy who makes his objective in life to be able to provide for tsun and make her happy. Here boon is kind of a gullible and shy brainlet who gets pushed around and takes a good while to figure out he's being bullied. It's more logic to think they're 2 separate entities who share the same appearance than trying to bend backwards into thinking he's the same guy from tsunbaka just because the ending of this oneshot is tragic.
The boon from tsunbaka would never kill himself because that would mean leaving tsun alone, the guy is a fucking boulder, nothing like this boon who killed himself because he had nothing left. He's dead, just deal with it.