I don't know if the common people of England were particularly aware of Henry Fitzroy. The nobles would have known about him. The only person I recall being accused of wanting to kill Henry Fitzroy was Anne Boleyn, and that was just before her execution, when Henry allegedly told Fitzroy "with tears in his eyes" that Anne had intended to poison him. Henry was making a lot of accusations about Anne at that point to various people, so you might want to discount the report.Fitzroy was pretty sick himself by that point, he died soon after Anne's execution, but I think that's the only reference to his illness being other than natural (he seems to have been consumptive, like his half-brother Edward and possibly his uncle Arthur).
I agree with foose. The only other rumour I read was from Hobden's 'biography' of Fitzroy - which is more a twenty-page first draft of an essay which sells on Amazon - suggests that Henry may have been behind Fitzroy's death as he feared a coup. The only 'evidence' she uses to back this is that Henry allegedly ordered the funeral to be done quickly and without any pomp. I certainly wouldn't agree with this or recommend the 'book' though! But it's an interesting rumour.
The mysterious funeral inspired author Tanya Huff to write 5 novels where Henry Fitzroy became a vampire. The books were recently turned into a TV series where you saw Henry the 8th's portrait hanging in Henry Fitzroy's apartment ;) bloodtiestv.com
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