I mean to say that Along with that family sponsorship case am i eligible to apply under Quebec Immigration Program ? ( A person can apply for Canadian Immigration under two different categories at a time ?)
You can apply for Quebec Immigration for two main reasons:
(1) as Leon said you can apply to more than one program given that you are eligible
(2) family sponsor is a 2 steps processing. First, your brother needs to file as sponsor and be approved. Until he's approved and a application is sent for Permanent residence by your parents and youurself, you do not have an application in their system. VO is only dealing with the application he has right now, once he's approved they cannot backup if he travels.
So, you do not have an application yet in the system unless you are in the permanent residence process .... and if so your brother was already approved.