After saving 20 rats from being tortured and trying to help them escape to Thorn Valley, I think he qualifies.
Honestly, I'm surprised no one proposed this guy yet from The Secret of NIMH since he saved most of the rats from NIMH and it's experimenting on rats, and tried to fight for their freedom by trying to drug Dragon, so I'm going to get started with this proposal.
What's The Work?
The Secret of NIMH is a 1982 animated film based on the novel Mrs. Frisby and the Rats of NIMH that centers on Mrs. Brisby trying to save her son Timothy from pneumonia and her family by moving the stone from the plow.
Who Is He?
Jonathan Brisby is the late husband of Mrs. Brisby and one of the two surviving mice of NIMH and the savior of the Rats and serves as a posthumous character in the series.
What Has He Done?
Jonathan was one of the mice kidnapped and taken to NIMH for experimenting and torture, which makes them become intelligent, until they were freed by Nicodemus. Unfortunately, most of the mice died from being sucked down an air vent, but the only survivors were Jonathan and Mr. Ages and Jonathan frees the rats by opening the gate, allowing their freedom as they escaped to Farmer Fitzgibbons' farm in the rose bush. The rats then tried to leave to Thorn Valley since the scientists would find them there and kill them, but had to get through Dragon to do so, so Jonathan volunteered to drug Dragon to help them with their plans and eventually got killed by Dragon, leaving him to die before the movie's events.
He served posthumously during the movie while Mrs. Brisby struggles to protect her family from harm and seeks help from others. He gets mentioned a few times during the movie and Nicodemus explains his heroic act during the middle part. Also Nicodemus explains that Jonathan couldn't tell Mrs. Brisby about NIMH because he would have remained young while Mrs. Brisby would grow old.
Admirable Standards
Now let's see about the admirable standards.
Mrs. Brisby: Who warned everyone that NIMH was coming and saved her children and Auntie Shrew from sinking into the mud with the power of the amulet.
Justin: Who defeated Jenner and led the rats to Thorn Valley to live peacefully.
Nicodemus: Who saved the rats from NIMH and tried to lead the rats to Thorn Valley like Justin.
Auntie Shrew: Who warned everyone about Farmer Fitzgibbon's plow, saving many lives in the process.
Sullivan: Who killed Jenner, ending his reign of terror, but fails the standards to all 4.
While the Admirable Standard is high, Jonathan passes it due to playing an important role in sacrificing his life to free 20 rats from NIMH by unlocking the gate and trying to lead them to Thorn Valley from the thorn bush since the scientists will track them to kill them by trying to drug Dragon for 4 years straight, until it costs him his life and having lesser resources. He also took great care of the Amulet until his death and requested it to be given to Mrs. Brisby, which allowed Mrs. Brisby to use it to save her brick home (with her kids and Auntie Shrew inside) from sinking into the mud in the end of the film.
Corrupting Factors
While he did try to drug Dragon, he only did it for the benefit of the other mice, since they would be killed by Dragon if he saw them, just like Mrs. Brisby did when she did the same. Other than that, he doesn't display any mitigating factors.
Also, the reason he didn't tell Mrs. Brisby about NIMH was so she wouldn't be bothered about the slowing age process effect it had.
Final Verdict?
I would say yes.