I agree with Alec: if you use it for people, "azuzar" has a negative meaning. One uses this for situations where someone makes other people do as he/she pleases by manipulating them as if they were inferior (like animals).
- Los azuzó para que pelearan.
- Los está azuzando para que terminen más rápido.
For the original example, I'd rather think of verbs like "motivar", "exhortar", "animar", "alentar". Or a simple "¿qué lo hizo volver a los estudios?"
