Spider’s mom died in the battle at the end of Avatar: The Way of Water’s backstory. The comics make that answer much clearer than the movie does.
The direct canon answer is that Spider’s mother is Paz Socorro, and she died during the final assault around the Tree of Souls.

Spider, also known as Miles “Spider” Socorro, is tied to both the human and Na’vi sides of Pandora’s conflict. The answer comes from Avatar lore outside the main movie, especially Avatar: The High Ground and related extended Avatar lore.
The Direct Answer From Avatar Canon

Paz Socorro is Spider’s mother. Canon places her death during the climactic fighting at the end of the first Avatar story.
The comic Avatar: The High Ground confirms that she piloted an RDA Scorpion gunship and died in the “last great battle.”
Paz Socorro Is Spider’s Mother
Paz Socorro is the woman behind Spider’s birth name, Miles Socorro. She had a connection to Colonel Miles Quaritch, which makes Spider’s family story more complicated than the movies first suggest.
She Died In The Final Battle Of The First Avatar
The comic version shows Paz dying during the huge battle at the end of the first film, near the Tree of Souls. She died in the same war zone where the Na’vi and RDA fought for Pandora.
The Death Is Confirmed In Avatar: The High Ground
Avatar: The High Ground gives the clearest confirmation of her fate. Her death is part of the battle itself, making the story feel much more connected to the main Avatar conflict.
What Happened To Paz Socorro In Battle
Paz was not just a background name. She was an RDA pilot in the middle of the war on Pandora.
Her death fits the larger chaos of the Na’vi fight against the RDA.
Her Role As An RDA Scorpion Pilot
Paz served as an RDA Scorpion gunship pilot, putting her on the human side of the conflict. That role connects her directly to the military push against the Omatikaya and the world of James Cameron’s Avatar.
How The Attack On The Na’vi Led To Her Death
During the final assault, the RDA and Na’vi battle turned deadly fast. Paz was caught in it.
Accounts of the scene say she was struck during the attack, which lines up with the wider destruction around Pandora’s sacred areas.
Why The Movies Barely Explain It
The films focus more on Jake Sully, Neytiri, and the main war. Paz’s fate is easy to miss.
Spider’s family history gets most of its detail through comics and other Avatar lore, not through long movie dialogue.
Why Her Death Matters To Spider And Quaritch
Spider’s story is shaped by grief, divided loyalties, and the fact that his father is Quaritch. Paz’s death is a key part of Spider’s emotional life.
Spider’s Family Split Between Humans And The Sullys
Spider grows up between worlds, with the Sully family on one side and his human roots on the other. That split helps explain why he feels close to Jake Sully and Neytiri, while also carrying the burden of his birth family.
What Quaritch And Paz Add To Spider’s Backstory
Quaritch and Paz give Spider a history full of conflict before he even appears in Avatar 2. The mix of love, war, and loss adds weight to his choices, especially when played by Jack Champion opposite Stephen Lang and Zoe Saldaña.
How This Could Shape Avatar 3
Spider’s mother, Quaritch, and the Sully family all hint at more emotional fallout in Avatar 3 and the rest of the Avatar sequels.
If Spider keeps struggling with who he belongs to, Paz’s death may stay central to his choices.
This could affect how he relates to Miles, Kiri, and everyone else around him.