I'm going to confront my mother about my 12 yr old brother being given shots
Why did your brother require shots?
He's been eating junk food for a while and he also doesn't get enough sleep
It is nice that you are concerned for the welfare of your brother. I am sure your mother is being careful and you should respect what your parent decides.
IT'S MY BROTHER! She should respect me; I'm his big brother!
A parent's concern for their child overrules that of that child's sibling. Unless you're your brother's guardian, you have no control over your mother's decisions regarding your brother's health. If you're really worried, just explain your concerns to your mother.