student responsibility for missing work

This year I told the students that if they are absent they will need to write an essay in Spanish for each day's work they missed. Their essays will need to incorporate the vocabulary they missed why they were out. Because of that I have given them extra days over the stated policy (1 day + number of days absent = due date) in order to learn the new words.

Well, I received an email arguing that I am punishing a student because this student has an illness which requires day-time doctor's appointments and involves time spent out of school. The parents are asking if I am perhaps breaking the student's 504 by requiring "extra work" for absences.

The school nurse defended my position and told the parents that I am in compliance with the 504. I also responded to the parents by explaining that the essay is really the same as doing the problems she misses in math class or the work for lit, etc. Writing an essay is the closest that I can approximate making up all the work we do in class. For the most part we are talking for an hour, which perhaps does not seem as intensive as other classes, but it's also much more difficult to make up. The students cannot possibly recreate the environment of hearing and speaking Spanish for an hour.

Really, I am just flabbergasted by the whole thing. I cannot fathom that asking a student to make up work from an absence can be conceived of as punishing the student for being sick. Is there any such thing as personal accountability anymore?