Begging for help?

Hello Visa Gurus,

Thank a million, a billion, a trillion in advance for your help!

My parents' passport will expire on 11-13-2010. Their visas are valid from 4-16-09 to 4-14-10. They are visiting us now and coming back to China next week (6 months stay). I would like them to come to visit us next spring again before their visas expire (4-14-10).
But I heard when they come in at the border, the visa officer only can give them whatever is left from the expiration date of passport minus 6 months. For example, if they come on 4-13-10, which is before their visa expire, at the border, the office only can give them 1 month, (stay until 5-13-10) because their passport will expire on 11-13-10. Looks like passport validity is at least 6 months before the expiration. My friend mom was given 3 months to stay in US becasue her passport validity was 9 months before expiration.

Could you please help me to know if this is true? And what we can do? I want them to stay 6 months. They can only come after April. Is that possible to ask passport office in china to extend their expiration date? But I know now they want to issue new ones instead of extension.

Please help. I am really frustrated. It's not worth to stay only one month and I don't want them to be tortured again at the US Consulate.

Thank a million, a billion, a trillion!

Frustrated Daughter