sister apply for brother

[personul22]

A person visited USA in tourist visa b1/b2. during this time, her sister got citizenship.
the question is can the sister apply for his brother during the time when brother still in US, or brother has to go back to native country?

If she can apply while brother is in US, can the brother continue living in usa and get his work permit until he wait for so many years and get his green card? or he must go back to native country before his tourist visa expires?

[immihelp]

He needs go back to his country. Sibling green card process takes around 12 years. Until the priority date is current, he can't file I-485, and until then, he can't stay in the U.S. based on that petition.

He can stay in the U.S. if he is able to maintain legal immigration status on his own, but not based on the petition by his sister.