My brother has fluid around his stomach has been drained once.. heavy drinker. cause? death rate?

Can't say...: ...With certainty. Can't speak to your brother's specific cause. But, when i hear about ascites (fluid in the belly) in a heavy drinker, it brings to mind liver failure from the alcohol, and cirrhosis. In such cases, when the cirrhosis is bad enough to cause ascites, there is a published mortality rate of 50% over the next two years.