I want to get some advice about this difficult situation concerning one of my PhD students.
Some time ago I wrote already about my status: I am assistant professor in Germany and very recently I got an offer for another permanent position abroad. I accepted it and in some weeks I will move there.
The problem I have is the following: my PhD student is paid from my personal grant that will be lost the time I will move (let me say that until very recently I didn't know that I could not move this grant, in part because I was not well advised. So now I do not have margin of negotiation with my new institution). However, I have had an agreement with the Department of the old institution and they will pay him from the remaining money of this personal project that I won in a competitive way (namely, this is not money from the department, strictly speaking).
The problem goes when I propose to the department a cotutoring: this means that I would be the advisor in my new location, and the head of my group (who completely agrees) to be the second advisor here. There are plenty of agreement between universities (at least in Europe) on this form, and in my new affiliation they are very happy about this idea and they have already provided the general agreement they use.
The problem comes from my previous institution: they just say NO from administration, and they do not give any other choice for this. So: what should I do? This seems to me very unhelpful, even more considering that the money will finish at the end of the year and a coadvising would help on the search of extra money.
Also, this would mean that officially they are proposing me to "forget" of being his official PhD advisor (after 1,5 years of work, which is half of the PhD this is unfair from their part towards me...).
How should I deal with this situation?
Let me mention that the main idea for this coadvising was that in this way we could ask for funding in a coadvising setting. This is necessary as in some months the money will be gone, and we need to get extra money for him to finish (6 months- 1 year)