Please Advise - Failed to get F1 visa due to dad's status


New Member
My niece was accepted as a graduate student in a university in US, but she failed to get the visa because I had applied immigration for my brother (needs another 8-10 years waiting time). My niece is already over 21 year old, even if my brother got approved, she still cannot come, I do not understand, why is she affected?
My questions are:
1) If she is over 21 years old, I thought she should not be affected by her dad's application, but why does it affect? She cannot come with her dad any way.
2) I am thinking to withdraw my brother's application, do you think it will help my niece to get a visa? or it does not make difference once you applied, no matter continue or withdraw?
3) will it help if I go back to China and go to the US Embassy in China together with my niece next time she is trying to get visa. Do you think will be helpful or can be worse? Will I be able to talk to the consular?