During the Inglourious Basterds' meeting with Bridget von Hammersmark in the basement bar, the bar's owner and bartender is always around and observing the events and ultimately taking part in the final shootout himself with the rifle he had under his bar. But it isn't entirely clear to me whom he's actually sided with. Seeing that he speaks German (while his daughter doesn't) and is played by one, this might suggest that he's supposed to be a collaborator but he doesn't seem too unsuspicious of the Germans in that bar either (though that might just be motivated by paternal care). Likewise is it absolutely hard to make out who kills whom in all the chaos at the end of this scene and especially what the barkeeper is actually shooting at.
So while this might as well have been left ambiguous, I wonder if there are any more conclusive hints at what the barkeeper's affiliation actually was, or just something obvious I missed. Was he actively siding for the Germans or was he just trying to protect his bar and shooting at any of those "troublemakers", no matter what uniform? Or could he even have sided with the Basterds (even if unbeknownst to them)?