Hypothetically, if it's a "one-off drunken argument" and the hypothetical woman wants to keep that partner, the hypothetical woman should ask herself why she pressed charges in the first place. Because the police and courts can't take it any further unless the hypothetical victim presses charges (unless the hypothetical victim is under age, or dead, or otherwise unable to take personal responsibility). Talk to the police.
Also hypothetically, the hypothetical woman should ask herself why she wants to keep that partner. Whatever happens with pressing charges or not, the hypothetical man should be dumped like the big piece of shit he is. And the hypothetical man should get his head around the fact that you don't hit women, whether you're drunk or not.