HDB owner inherits HDB. Can't sell in lousy market. How?

I have this hypothetical scenario.

X owns existing HDB. X's parents passed away and X inherits HDB. HDB rules mandate X must sell one of the HDBs within 6 months. X decides to sell parents' HDB. However, he cannot find a reasonable buyer at a reasonable price after 6 months. What happens? Will HDB force-sell at unreasonable price? Any one been through this situation?

I expect many Singaporeans to face this problem because of aging population who own HDBs and are near time to die.