Evidently, the scanner didn't turn off unsharp mask when he scanned it. Thus, the entire scan was basically ruined. The half-tones are only part of the problem. The page is overall too sharp. There's no way you can fix that. Filtering it, even lightly, will only make it worse.
I'd recommend looking for a better raw. I'm going to go ahead and deem that one as "unfit for scanlating".