@Chilon.
Officer Sicknick did not die from injuries received on Jan 6th as was widely misreported by the media. Your link is from an old article that evidently never got corrected. At one point the media even reported that he suffered injuries form being hit with a fire extinguisher--once again false. He did get pepper sprayed but the coroner said there were no lasting effects from that. An autopsy revealed that he had no injuries but instead died from two successive strokes which occurred the day after the riots. For some reason the coroners report was kept from the public until April which is probably why some incorrect original reports still can be found on the internet.
https://en.wikipedia.org/wiki/Death_of_Brian_SicknickOn April 19, 2021, the Office of the Chief Medical Examiner of the District of Columbia issued a press release about the death of Brian Sicknick. It said that the manner of death was natural and the cause of death was "acute brainstem and cerebellar infarcts due to acute basilar arterythrombosis" (two strokes at the base of the brain stem caused by an artery clot).[31][29] The term "natural" was used to indicate a death caused by a disease alone; and if an injury contributed to the manner of death, it would not be considered natural.[31] It took more than 100 days to release these results from the January autopsy.[25] The full autopsy report was not released to the public.[31]
Whether the stress of the event contributed to the stroke is pretty speculative at this point.