Looking for some advice really, in the past 6 months DS has decided to go back to work full time and leave nieces with different family members. This change in dynamic has resulted in DN (4yo) behaviour becoming unbearable (hitting, spitting, running out on to road etc) the problem is , DS and brother in law laugh these behaviours off and don't seem to mind said behaviour. Recently, DD (3) has started copying DN whenever we are around them.
How do I stop DD from doing this? We have worked very hard on DD behaviour the past year and now I'm struggling on how to stop the copying. And advice would be much appreciated.x