Hi Nadja,
recently no, lastly I get seeds from him at the begining of this spring. Under my conditions I had unsatisfactory germination rate... But I hope that you will have bigger success than me
However, here is some batch to get an idea.
From what I see in the pics this definitely is NOT mildew or some kind of fungus! This more looks like a sunburn or it is caused by small insect or something....
Check the roots, obviously they are rotten. At this stage u can't do so much unfortunately. I would pull out this plant, wash the roots or what is left from them and put place only in live sphag, nothing else.
Looks good even it pottet in straight peat. However, the climate in Romania is the same as in Bulgaria, so put your plant outdoors in full sun as much as better from spring to autumn. In winter at the window in your room.
I use orchid fert with no Urea full strenght when I water the roots and 1/3 strenght when I use it as foliar. I have used osmocote but see no difference.