It's not ideal, but if he can put himself in a position where it's obvious to management that the project didn't fail because of him, I don't think he'll end up

It's not ideal, but if he can put himself in a position where it's obvious to management that the project didn't fail because of him, I don't think he'll end up too badly off. If the parts of the project he's worked on are well put together and working well, then it doesn't look too bad on him that the overall project failed. On the other hand, it sounds like a depressing situation to be in, so I'd prefer your option (b).