Bad mood???

Sounds like at the present time your older brother may be in need of some additional guidance from your ma and grandma. If it becomes too upsetting then please do tell them what is upsetting you and hopefully they will try to accomodate your feelings also. But realize that at this moment in time although they may not be showing it they do love you as much as he but just think that he needs their help and guidance a little more then you. Sounds like your a pretty good kid and pretty self aware and mature for your age so continue to be like this. Trust me when I tell you how much your behaviour makes it easier on them to try and overcompensate with your brother. But soon enough things will return to normal and then hopefully everything and everyone will be on equal footing once again.