The dead author wouldn't have been a problem for the manga version continuing, and the short manga wasn't a problem for the animation, because the original novel it was based on was already done years before the author died. Both the manga and the anime were clearly just those "buy the novels for the rest" sort of deals.
There's actually an ongoing novel series by that author, because the draft was completed prior to the death, and the publisher has gone forward with it since. That also seems to have a short manga adaptation that's barely worth starting to scanlate because it's already done and was probably just for aiding novel sales too.
I quite liked this. It was more tender and had more interesting characters than a typical ecchi harem manga. The amount of parodies and shout-outs to other series was quite high, and they were funny, too.