what do i have to do to adopt my sister and brother.Instead of them getting adopted by someone else, is it possible for an 18yr

In Georgia, one must be at least 25 years old OR married to adopt. The would-be adopter must also be at least ten years older than the adoptee(s). (See the Georgia Code in OCGA 19-8-3).

Your mother's parental rights will not be taken away lightly. Of course, a successful adoption procedure would remove them.

The state may also take away her rights for, among other things, failure to provide necessities to or cruel treatment of your siblings (OCGA 19-7-1). Cruel treatment has been defined in one case as "willfully and maliciously exposing child's life and health to dangers." (Wright v. Wright, 85 Ga. App. 721 (1952)).

She can also contract to remove her parental rights. Of course, this implies she does so willingly.

One can become a guardian of a child without adopting him/her, but first all living parents (father included) must lose their parental rights. There are also requirements for becoming a guardian that must be met. The probate court will not appoint one lightly.

I would recommend talking to a competent attorney. I'm in LaGrange and available to help if you're interested.