Extending stay for mom in law

Hi,

My mom in law will finish her 6 month stay by Mar 27. I want to extend her stay for another month. Her B1 visa is expiring on May 10. Is it okay to extend the stay when her VISA is expiring very soon?

Visa is only a travel document required to enter the US.
If her I-94 is expiring in March, you will need to file an extension request with a valid reason. I would suggest against doing it unless there is a substantial valid reason.