Sounds like a great way to brighten his day! Go for it!!
On top of everything else that has been said, we have no idea what the man's financial situation really is. My experience with folks his age is that many will pinch pennies and scrimp and save even when they have hundreds of thousands in the bank. More often than not that's why they have so much squirreled away. At 80+ years old, if he wants a beer and it isn't going to kill him, let him have a beer.
I have also known many more active "rich" alcoholics than "poor" ones. The rich can afford the booze. The poor are often limited to skipping the booze to get a little food. Old poor folks with housing typically make pretty good decisions about priorities.
My Dad loved his beer and whiskey. By the time he was in his 80 I would have loved to share my homebrew with him but he had advanced Parkinson's Decease by then and never got to taste a single drop of it. Let you friend enjoy his twilight years and pray you get the chance to, too.
Be happy with what you have, share what you can, try to live like you're dying and you won't have any regrets when you come to the clearing at end of your path.