He should definately have not shown you during his applicAtion. I know it sounds fishy and not right, but it is what it is. Since, you came in a student visa and now you said you have a green card, it is obvious that your brother can be held accountable with the intent of immigration.

Sometimes keeping silence is better.

 Well, I have shown him in my relationship verfication as my brother. My parents visa when they came to attend in my graduation had shown him in the relationship verfication. So i couldnot have hidden myself this time. But those things apart, does that mean if you are permanent resident in US, your brother cannot come here to study? I have seen siblings staying and working here. I wonder if given my conditions, someone could suggest on his experience.

F-1 Visa gets rejected due to number of reasons.

Mostly due to fradulence in documents which all young kids tend to do because they so much rely on these idiotic educationa consultancy's advices, like do not show your siblings who is in US, do over valuation of your property, show a lot of income of your parents from rents etc etc.., forge /prepare unrealistic bank balance..etc etc..if you did that you are likely to fall in trap.

Second is, if your bro is coming for undergrad then they would have gone for every inch of his documents including his previous academic credentials.

I do not think your sponsoring him would have made any difference in rejecting his visa, because every tom dick and harry can sponsor and write a letter with bank statement.

If you ask the "rejected group" they would never tell you a right story about  forging the docs and telling lies, making unrealistic arguments . such as " I am a good student of good family background etc etc"..i have seen many times those people getting rejected and those who answer everything confidently with genuine doc, I have seen them a lot of time getting VISA. 

My suggestions for him  -present genuine documents, and just to be on the safe side and avoid further questions regarding you, get rid of your name as an sponsor ( they know how difficult it is to make money and save $$$$ per year, let alone sponsoring others) but mention your name in relationship certificate. Help him trailor his resume as per US-format..and tell him to be confident and go without fear of being rejected!!  Good luck!!

Thanks Kanchu,  since my parents are retired , i have to show myself as a sponsor to show credible source of income. I have tried to prepare my brother in his interview and motivated. how other ways can we divert consular attention from me ????

head on , i understand your frustration, even your parents are retired, you can still show the savings and tell them they are retired and if they have provident fund, pension etc . .you can show that too. they know many nepali do not have $ 40,000 in saving account ..what i would advise is tell your brother to attend the visa session organized by US embassy and asked few questions to the couselor, mostly those who come on orientation program are the couselors who takes the interview..

 if the guy is genuine student and genuine intention to study in a decent university  , who has decent academic credentials are very likely to get visa, financial documents are not something that they would look first..this is what they told when myself attended one of those seesions organized by embassy. 

tell your bro to do all the homework to gain confidence..and tell him to be genuine!!

@ head on -
I have been through your pain . I did had GC in USA . When my brother wanted to come to us for Undergraduate He was being denied with the same reason . So Looks like if your siblings has greencard , It is very hard for them to give student visa . Its been 2 years i have sponsored him with I-130 ( Immigration Process ) , I am sure he cannot get the visa for his Graduate degree.
"They are thinking that You are going to apply for GC for your siblings then they won't return back " as if all other students have returned back .

It is very frustated and painful but life goes on . what else can i say ?

While I came to the USA, my brother had a green card. He sponsored me and got visa. The visa officer said, you are qualified, and did not asked more than 2 questions. Now I think, I was lucky...

 Two criterias that need to fulfilled to obtain visa - 

1. The candidate needs to prove that he can financially afford his college education.

2. Prove that your ties with the States are very limited and you're likely to return back. 

Seems like your brother managed to prove that he can afford to study in the US but in the eyes of the embassy, the likelihood of him returning back after Graduation are slim. It's retarded but that's the way it is. 

Why don't you have him apply to a University in Canada or Australia? He already has decent credentials by the looks of things. 

Head on, how did u get your greencard? EB2, asylym, DV??

 EB2.

since you changed your status from f1, there is almost no probability of your brother getting a visa.

Well i found your conclusion unreasonable and immature. How many who entered in f1 visa remain in f1...eventually they will turn to h1b and greencard. its obvious. Also there are many persons whose siblings now reside in US. Even in USembassy webchat regarding f1 visa ..they say about siblings residing in US that the student needs to provide enough ties to the country.  Simply because i had green card doesnot prove my brothers intend to immigrate, it creates the suspicion which is absolutely dependant on the mood of the consular. My expectation from the sajha community was....how can we convince the intent to return and not immigrate.  FYI when i was a student. one of my roomate brother was the US citizen here...who entered US as a student and married to US citizen later. This was not obstruction for him. But again it was 7 years ago...and i donot want to create an argument. 

It is a very subjective matter. It is not illegal to change the status from F1 to whatever else it is as long as their immigration laws allow. Yet I cannot understand the way the visa rejections take place. Of course there are cases where the kids dont even know what they are doing and blindly follow some education consultant's advice after paying a hefty sum to those blood suckers and I am sure that it's that kind of culture which puts the rest of the mass in the same level of scrutiny. A lot of kids even tend to shy away from taking toefl, sat or gre. They would rather resort to some blood sucker agent's advice as if they do not have their own back bone, who makes it look like migrating to USA is the solution of all the problems in life.

I guess all I can say is that be straight with the interviewer. Make it a case to let them know that you need to come back since your brother is a US citizen now (and that he has not broken any laws by taking up the new status) and that someone needs to be back in Nepal to take care of your parents and that you have other plans after your school is over.