The subject of my post is how do I approach him about it. Not all the reasons why he's gained (though I did include that it is due to the amount of beer he drinks) not what his health status is... How would I know what you or any other commenter would consider "relevant info"? I can't include our whole life story here, no one would have the patience to read all that. I'm asking for the best way to talk to him without me getting shut down and him getting hurt.

I most certainly welcome people to ask questions! But there's a kinder way to do that than the way you went about it, and I think you know what. Here's an example: "That much weight gain in a short amount of time is concerning. How long did it take for him to get that size? Has he been to a doctor? Have you noticed any other issues?"

It's easy to tactfully ask for more details. It's appropriate here to consider that I have valid feelings also, and I came here for help from others who were successful in navigating a solution, not to be talked down to.