“The spread of melanoma to his lungs and brain caused his death. His final words to his son Ziggy were “Money can’t buy life.” wikipedia
You are correct but the brain was involved
That is a secondary metastasis from the primary melanoma.Just like spread of a primary to the bone is not called ‘bone cancer’ this is not called brain cancer. Those terms are saved for primary cancers of the bone and brain, respectively. And it has nothing to do with marijuana as you also said.