Cats do not fare as well as dogs. Far fewer worms can cause death in a cat than in a dog, and there is no effective, safe treatment. Some vets will use meds that kill the worms but have a very high complication rate. Some vets will just treat any symptoms and wait for the worms to die on their own. The worms themselves can cause complications, even if the cat survives.

Even strictly indoor cats can get them, although the chances are far less.

Prayers for your step-mom's kitty, cprince.