As subtle as Amelia is trying to be, Adia can tell that her question isn't hypothetical. She leans forward, brow pinched with worry. Who is her friend worried about? Steve, maybe?
He could certainly due with a healthier set of lungs, but a better immune system isn't much help against blunt force trauma...

It's a morbid thought, and she pushes it roughly from her mind. Unfortunately, there isn't any sort of helpful, uplifting answer to take its place. "It depends on what part of the immune system is weak, but possible therapies vary from person to person." She tugs a little at the ends of her scarf and adds, "Sometimes the best solution is preventative. Vaccines, hand-washing... making sure they aren't around anyone who's sick."