There is much more to this story than that single letter, but I am not allowed to share the other info I've been relayed.
It's poor PR for QR, but I dare say there will be repercussions for the employee.
In terms of the Training Debt, it is quite normal for Flight Crew to carry that debt with them to different airlines - it gets paid off over time, and if an airline needs flight crew they will usually offer to pay any existing training debt (EK and many China based airlines operate like this).
M