And? Pretty sure it won't matter since that's probably Yoda coming back, but the son-in-law can just describe the guy he's looking for. Something like "he has black hair like you". If the staff says "don't remember" or starts asking shifty questions, only then it's time to be worried.
But this guy is already freaking out this much just wondering if Yoda was there or not. There was no reason to overthink this too hard because it's literally not a big deal to ask if a friend/a relative had been around or not. It's a tavern, nobody would think it's weird if you just ask that.