First of all just let me begin by saying that I am not in support of Durmstrang closing. If there can be a solution for still having the school on board, maybe by reducing the number of forums or subtopics and just making it less extensive, I would be totally game for that.
If absolutely nothing can be done, there is still the matter of the multiple students that are currently studying in Durms and don't want to shift. Maybe taking a survey about the number of students willing to shift and the number of students wanting to graduate in Durm - and then formulating a plan about helping them graduate from the school? While people can still work around other things in terms of the story line if they are adult, the school in itself is a big part of development for the student characters. And nobody wants to rush their character through school without any development. That just creates adults with no backstory and no plots and well, writers lose muse on such characters. While its my understanding that we have till end of fall term, that is still not enough for people having students in younger years. An extension in the timeline would certainly help in this regard as it will be lesser pressure on writers to gain quills and graduate from Durm, but then it all depends on the number of students who still want to graduate from Durm. Hence, the survey.