Thanks cs for your reply. I am actually a Singapore citizen, and I realise that marriage would probably be his best chance of staying here. However I was trying not to exercise that option simply for reasons of convenience, but I guess this is how the world works now. I don't think he is really looking for a PR; he's looking to work here on an employment pass for a few years before moving on, or, if he decides, getting his PR.
Reading your reply and the other messages on this board, it does seem that the situation isn't as easy as we'd imagined it to be. But what about this 'employment eligibility' pass? Isn't it something that you can hold so you can stay here and look for a job? He holds a post-graduate degree, does this make a difference at all?
Again, thank you. Government websites seem vague and superficial when it comes to addressing issues like these.