LE vs LES

hace 6 años

Hello, I've come across a sentence that seems wrong, and I don't know what it is I don't understand about the grammar that translators seem to say it is right, and including native speakers.

The sentence is...  -¿Qué consejo LE da Maria a los estudiantes mayores?-

I translate this as...
What advice does Maria give TO the older students?

My issue is the LE in the sentence. Is it not an Indirect Object referring to the Older Students?
Are they not plural?
Why isn't LES used then instead of the singular indirect LE?

i.e.  Why isn´t the sentence ... -¿Qué consejo LES da Maria a los estudiantes mayores?

-Kirk