I cannot replicate the problem, oddly? Altering the defaults for folder views changes nothing. The only way I can get a separate window is by right clicking in the Nav pane and selecting "Open in new Window." That opens a new instance of Windows Explorer, with the folder, of course.
Even if you have set your preferences to open in SAME folder... as the default is set - See my image - red circles
When you click on a folder in the RIGHT plane it will open in a new window.. but if you click on a folder in the LEFT plane it will expand in the same window. It's just a matter of where you click ... in my example on CDL.
He seems to be "annoyed" when a new window opens when he clicks a folder. If he clicks on the left plane a new window won't open. He must be clicking on the right plane ... not realizing there is a difference.