Ingeborg, I'm sorry you and your family are going through all this. We are here for you so vent and talk all you want.

I wonder if your husband's behaviour has anything to do with the frightening feeling of not being in control when cancer strikes.
The treatments, the procedures, what will happen to him, everything is new and unknown. If he is a tidy and precise person as you describe, there is only a "right" way or the "wrong" way that things are done. This may become magnified as his way of coping with the loss of control.

As treatments continue, you will both become more familiar with procedures and the "control" issue will hopefully stabilize.
Plus, when he gets good pain control meds, he will likely mellow out.
Ginny