I have been in a relationship with a man for over 2 years. It has been a loving relationship with little problems. We discussed marriage, etc. His father recently passed away unexpectedly. A week later, he found out his mother has cancer and has to undergo chemo. (His parents were divorced when he was very young.) Two weeks after all of this happened, he told me he needed some space but wouldn't be specific about the timeframe. I asked him if we were breaking up and he said "no". Two weeks later and he won't answer or return my calls. Is he seeing someone else or trying to sort out his life? I'm stuck in limbo because I do love him but I don't know the status of "us".

I think he is depressed. He needs some time to get his life back on track. I highly doubt that he is seeing someone else. The best thing you can do is be there for him and make sure he knows that you are there for him. You probably won't know the status of "us" until he is mentally stable to start where you two left off.
Best of luck to you both.