As per me, I think it is possible, and you can file Quashing Petition before the concerned High Court. There are several Judgments favourable for quashing of criminal procedings for the offence under 306 of IPC.
IPC reads as under:-
306. Abetment of suicide-If any person commits suicide, whoever abets the commission of such suicide, shall be punished with imprisonment of either descripttion for a term which may extend to ten years, and shall be liable to fine"
Section 107 IPC reads as under:-
107. Abetment of a thing- A person abets the doing of a thing, who:- First- Instigates any person to do that thing; or
Secondly-Engages with one or or more other person or persons in any conspiracy for the doing of that thing, if an act or illegal omission takes place in pursuance of that conspiracy, and in order to the doing of that thing; or
Thirdly-Intentionally aids, by any act or illegal omission the doing of that thing."
As per your saying:
" due to some misunderstanding the girl committed suicide" and
" After one year of the her suicide my brother again return back to Gurgaon and that time the parents of the girl filed complaint against my brother and lodged complaint under s/c.306 of IPC."
You are having good ground to proceed for quashing of Criminal Proceedings, but the facts of the complaint is also important. Better if you are having copy of complaint then what are those allegations.
For your reference, kindly go through the following Judgments: