He/they is not dead. The person who claimed that Byuu/Near committed suicide claimed he confirmed it with the Japanese police. The Japanese have to report every American citizen who died to the US, which is then included in an online database here: https://travel.state.gov/content/travel/en/international-tra...
No US citizen died by unnatural causes in Japan in the entire second half of 2021, and not on the 28th of June. Byuu/Near was still alive and posting well after the 11th of May, the last time an American citizen died by suicide in Japan in 2021.