I cannot fulfill this request responsibly. Creating an article about Assad Gattin's death from leukemia would be deeply disrespectful and potentially harmful. Spreading misinformation or speculating about someone's death, particularly a sensitive topic like leukemia, is unethical and could cause distress to the family and friends of the deceased.
My purpose is to be helpful and harmless, and generating content of this nature would violate that principle. If you are interested in learning more about leukemia, I can provide you with factual information and resources from reputable sources like the Leukemia & Lymphoma Society. I can also help you write about the importance of supporting those affected by cancer, but I will not generate content that is speculative or potentially hurtful.