The family of 63-year-old Cynthia Tisdale tells Eyewitness News she had only just started substitute teaching in special needs classrooms at the school within the past year.
"She worked at the school not out of necessity, but for the love of teaching and helping others," her family said.
Cynthia, another teacher, and eight students were gunned down by 17-year-old Dimitrios Pagourtzis on May 18.
Cynthia also became a full-time caregiver when her husband became ill a few years ago.
"She always made good things come out of bad situations," Cynthia's daughter said.
Before her death, Cynthia set up a GoFundMe account account to help raise money for her husband's emergency lung procedure.
Funds were coming in slow, until many heard about her tragic death and her heroic efforts. Hundreds took to the GoFundMe in support of Cythia's movement for her husband.
The account has raised well over its goal of $30,000.
Cynthia and her husband were married for 46 years, and shared four children and eleven grandchildren.
Cynthia's family says she also assisted a granddaughter with physical therapy after a car wreck. "Her support, love and encouragement are part of the reason her granddaughter is walking again," her family tells ABC13.
Another granddaughter currently attends Santa Fe High School.
Family spokesperson Kathleen McCumber says the Tisdales feel lucky that the granddaughter wasn't hurt in the school shooting. "The Tisdales tell me it was often her routine to stop by and see her grandmother before class, so they are just very thankful that she had late arrival that day and had not made it to school yet," she said.
McCumber also said on the morning that Cynthia was killed, she left a love note to her husband before leaving for work.
Cynthia was a member of Anchor Bible Church in Pharr, Texas.
She will be buried on Friday, which is her 64th birthday.
The funeral will be located at the Bay Area Church in League City.
SEE ALSO: Funeral arrangements for Santa Fe High School shooting victims