As we progress further into the series we start seeing more faults of Sakura's guardian/mentor, Kero. In fact, this episode is a prime example of how immature Kero can be. C'mon, dude, you're like at least 100 (maybe?) and she's 10.
But that doesn't mean Kero doesn't step up to the plate every now and again, and frankly if he didn't help take care of a 4-year-old latchkey kid then he'd just be the worst. So there's hope for him yet!