I faced multiple challenges as a teacher in a University, in Central American country. I was teaching students who would eventually be teaching English in primary schools (provided they PASSED my course). One of the challenges I had was that so many of my students weren't even at the academic level of English themselves to be able to grasp much of the materials in the course load. Here's the issue - if a student doesn't do well in a prerequisite (repeatedly), then a reasonable "fine" would be paid to the Uni and the student would be allowed to move forward in classes. This resulted in a classroom in which about 70% of my students were NOT prepared for the current material.
What would you have done? Failed them all, passed them all, "bent" the rules so that a number of them passed...? I'm curious!