Visitor Visa - B2

Dear friend,

I have B1/B2 visa i visited to see my family in washington D.C on 30th June,2017, & return back to my home country on 21st october, 2017 but now my grandmother is not well & is hospitalised & is very serious....Doctor said her chances of leaving is less then 6 months...

I came back in 3 months & 21 days from D.C, now my uncle has moved to some other states for job......but my grandmother is in nursing home in D.C & is taken care by nursing staff in the hospital......I & my mother is planning to go USA again.......

I just want to know that can i go to some other states in USA where my uncle resides or is it compulsory to go to the states in D.C only where i landed first with the stamping of washington D.C

I am confused what should i do & remove tickets of whcih states......As now in D.C my uncle does not have his house & now he has his house in some other states in USA.....Please advise as what should i do.....you can post your suggestion & advise me