My Brother Is An Alcoholic And Has Been For Most

My brother is an alcoholic and has been for most of his life -he is now 55 years old. He has diabetes that has damaged most systems in his body. He has nerve damage in his feet and a swelling on one side of his chest/abdomen area. My sister wants him to fly to her house for Christmas -is it safe for him to fly? Is this enough information to be able to answer?