It has been abandoned, hasn't it? Why is no one encouraged to continue them? I don't think he'd be upset if someone continued his work, it's not like it's an appropriately moral thing to do.... There are many games that are good and never finished, and I understand that the "sketches" are there in the database and someone with good experience can use them, to continue. I don't know if I'm wrong. It's like a mod, if someone abandons it, but leaves the trace or the source, they can continue it.
I have many ideas for games, and I even know how to draw and illustrate, if I could use those programs to make games, I would make games for everyone. I have time, because I am sick and my only distraction, is the internet world.