How does Georgiana Maria Gargary treat Pip?

In chapter 2, Pip says that his sister, Georgiana Maria Gargery (usually known as "Mrs. Joe"), brings him up "by hand." By this, he means that she hits him repeatedly and treats him abusively. She is twenty years older than Pip, and she raises him after their parents died.
Mrs. Joe is verbally abusive to Pip. When Pip has been at the churchyard and she does not know where he is, she addresses Pip as "you young monkey." Mrs. Joe is excessively strict, and she expects Pip to comply with all her wishes. When he seems unwell, she administers Tar-water to him and holds his head as "a boot would be held in a bootjack."
Mrs. Joe is in a perennially bad mood, and she is a rigorous and excessive housekeeper who keeps everything in her house so clean that the house becomes uncomfortable to those around her. She is verbally and physically abusive to both Pip and her husband, and she seems to resent having to raise Pip.

Like many of the major women in this novel, Pip's (much older) sister is not a pleasant person. She is unkind to Pip, resents his presence, and abuses both Pip and her kind-hearted husband, Joe. She frightens Pip. Pip and Joe bond into a closer relationship because they both have to lean on each other to withstand her.
Pip says of his sister,

I had known, from the time when I could speak, that my sister, in her capricious and violent coercion, was unjust to me.

Pip knows that his sister's temper tantrums, and the way she slaps and hits him, are wrong. He says it contributes to making him timid and sensitive.
Pip is almost as afraid of being caught by his sister while he is stealing food and supplies to help the convict, Magwitch (who is hiding in the fens), as he is afraid of Magwitch. Mrs. Joe provides a stark contrast to people like Joe and Magwitch. Although she is Pip's flesh and blood, men who have no blood relation to Pip act more as real parents to him, nurturing him and caring for him.

Pip's sister is a thoroughly unpleasant character with her shrewish tongue, abuse of both Pip and her husband, incessant complaining, and deliberate troublemaking. Dickens evidently created her to serve as a contrast to her kind, patient husband Joe. She cannot appreciate what a good man she has. But the author undoubtedly had a deeper purpose than that. He wanted to avoid suggesting that all working-class people were good and all upper-class people were bad. Dickens was more religious than political, though he dealt with the sufferings of the poor and underprivileged in so many of his works. Mrs. Joe Gargary and the surly Orlick are examples of working-class people who are not kind and good, while Herbert Pocket and his father Matthew Pocket are examples of upper-class types who are not cold-hearted and parasitical.
https://www.owleyes.org/text/great-expectations/read/chapter-ii