I suggest you read the obituaries (his English writing pretty much stops in 2021).
The obituaries tell the tale and frame the background. And correction: he worked for Breaking the Silence, not Gisha. (I think he did some projects for them.)
He was a good man.
https://mondoweiss.net/2023/02/a-farewell-to-the-inestimable-yossi-gurvitz/
https://www.972mag.com/yossi-gurvitz-obituary/