Fidel Castro's first son, Fidel Ángel Castro Díaz-Balart AKA "Fidelito" killed himself after a failed depression treatment. I couldn't find any details, as this was reported by Cuban media.
He was part of the council in charge of science in Cuba and tried to pioneer a nuclear power program there, without success.
Many details are blurry and people theorizes about an "assisted suicide".
https://archive.fo/fHqmI