If there is a real estate crisis in fact or in evolution in China then it would seem that the Yuan (RMB) would have considerable difficulty in replacing the dollar as the world's "Reserve Currency".  For a counter argument suggesting that the RMB might prevail over the dollar see the link below:

Could China’s Yuan replace the U.S. dollar as the world’s dominant currency? Here’s how the Asian nation's trade supremacy is rapidly boosting its reserve status (msn.com)