Ok, he is living in it now. And what is cracking now? Transitions between wall/ceiling or the plaster/the wallpaper in the wall?
He is certainly allowed to take pictures inside his own house now, right? How many weeks/months have passed since the screed/move-in?
It can't be that difficult…
He has been living in it for a year now.
Attached are a few of the spots that have cracked. But there is practically no wall in the house without a crack.
How is the surface, is it just plaster or is there [Malervlies] underneath? We only have plaster, so it is normal for it to crack, for example, in the corners and transitions or also in places where, for example, the ventilation is installed, but it is already quite a lot with you.