Claire Davis, a 17-year-old senior, remains in critical but stable condition in a coma after she was shot at point blank range by the gunman, 18-year-old Karl Pierson.
Chris Davis, a fellow senior who is not related to the victim, has started to collect donations to help pay for her medical expenses. He says he has raised $4,000 in the last 48 hours. He plans to make online donations possible by Monday.
Chris Davis does not know Claire Davis personally, but said he often saw her because her locker was near his.
"I feel like it's going to make us a stronger senior class and school as a whole," said Chris Davis.
Claire Davis' father on Saturday told affiliate KMGH-TV his daughter was "not doing very well" but he was grateful for the community's outpouring of support.
Pierson was armed with a shotgun, machete and Molotov cocktails, police said. Police also said Pierson was seeking "revenge" on the school's debate teacher, who had dropped him from the team.
Claire Davis was sitting with a friend when Pierson entered the library and shot her in the head. Authorities say she appeared to be a random target.
Hundreds of students held a candlelight vigil for Davis Saturday night at a park near the school.
Meanwhile, a friend of Pierson says there were warning signs before Friday's shooting. Joe Redmond says Pierson threatened his speech and debate team coach on a recent trip. Redmond says Pierson was never the same after he was suspended in September.
"He went to nationals with Mr. Murphy, and I know they did not get along on his trip to nationals," said Redmond. "Karl has threatened to kill Mr. Murphy half-jokingly, Mr. Murphy brought that to the administration and Karl was suspended for that."
ABC News and the Associated Press contributed to this report.