Hema is Missing Hospital's only obstetrician/gynecologist, and she's also the adoptive mother of Shiva and Marion. She delivers them to the world and tries to save their mother, but when she fails at the latter, she protects the twins fiercely, as if they were her own. Let's figure out what makes her so tough.
When we first meet Hema, she's flying back to Ethiopia after a trip to India. When the plane loses power and starts to fall, a little boy falls into her lap, and she realizes that she wishes she'd had a child: "As she bent over the child she realized that the tragedy of death had to do entirely with what was left unfulfilled" (1.3.54).
Well, her desire is fulfilled almost immediately, though not quite in the way she'd expected: when she gets back to Missing, she has to act quickly and deliver the conjoined twins her friend Sister Mary Joseph Praise has secretly been carrying for nine months. When Sister Mary dies, Hema becomes the default mother of the babies. She acts as though she herself had gone through labor.
When Ghosh asks her to operate the next day, Hema's reply is, "'If they are so desperate, they can open the belly themselves. I am an obstetrician-gynecologist. Tell them I just had twins and I'm in no condition to operate'" (2.13.59). Hema slips into motherhood so easily that she feels a biological and unconditional connection to the babies. It changes her life completely, and she never complains once.
You might think that someone as maternal as Hema would be a pushover. You'd be wrong. Remember that plane crash scene? Turns out it was just a stunt on the part of the pilot. Hema's response: to squeeze the pilot's junk in her hands until he almost passes out. That's one way to deal with it, we guess?
Once Hema's forced the pilot to repay everyone's money and pay for the hurt child's injuries, she acts like it ain't no thing: "'Well, how can one be sane in hot weather?' Hemlatha said to no one in particular, letting go and making for the outside to wash her hands, stifling her laughter" (1.5.31). She acts as though she's "insane," though she laughs, showing that she really approves of her actions because she's fighting for the right.
The point seems to be that Hema takes life and death seriously, and she's not going to suffer anyone making light of either.
For the rest of her life, Hema will show courage. She shows courage when Ghosh is arrested and when he dies, for example, and she also shows courage when Marion is in a coma and when Shiva dies after donating part of his liver. This lady is one tough mama.