Breakdown of Mi gato va a empeorar sin su medicina.
el gato
the cat
mi
my
su
his/her/its/their/your (formal)
ir
to go
Questions & Answers about Mi gato va a empeorar sin su medicina.
Since this lesson is about lo de, how would I use it here to say 'The situation with my cat is going to get worse'?
Where does the verb empeorar come from?
It is built directly from the comparative word peor (worse). By adding the prefix em- and the verb ending -ar, it becomes the verb meaning 'to get worse.' You can see the exact same pattern for the opposite meaning with mejorar (to get better), which comes from mejor (better).
Since the cat's health is undergoing a change, could I use the reflexive empeorarse here?
You could, as empeorarse is sometimes used when talking specifically about someone getting sicker. However, the non-reflexive empeorar is completely standard and heavily used for health, weather, and general situations, so you don't need the reflexive pronoun here.