"We are here primarily for your safety."

This is one place that this mantra could come in handy.

If the person is seriously falling-down drunk, you can tell the FA "This is a safety issue because ...," with the "because" being, for example, that he might block others in his row from reaching the exit or anything else that fits the situation. That will get the FA's attention, fast. If they don't do something about it at that point they could be in serious trouble - and they know it. (They also know that anyone who knows enough to put it that way might be in a position to cause them serious trouble if they don't.)

I wouldn't do this just because someone is a bit noisy, and as previously posted the specific situation in this thread is at best hearsay, but it will work.