If I only worked 3 months and made about $1200.00 dollars and my mom is on social security disability and my brother did not work if I claim them both and head of household about how much will I get back?

Denny - you can't claim to be HoH unless (a)you provided over half the upkeep for the home (rent, utilities, taxes, mortgage, etc), and (b) you have a dependent. To claim your mother or brother as a dependent:
(c) you must provide over half the person's upkeep for the year, and (d) the person must have less than $3500 income.

Given that your mother is on SS disability I'd be surprised if she qualifies as your dependent. And also I'd be surprised if you, and not she, paid to maintain the home where you live. Besides, if you only made $1200 for the year then you can get all your withholding back anyway -- unless you are a dependent yourself, in which case there's no point in even considering HoH.