Loving Dad,
What new behaviors are you trying? How is she reacting? If you can be more specific we might be able to offer you more pointed guidance on our own experiences and how using tools and the lessons have worked (or not worked) for any or all of us.
Why are you with a friend instead in your home? Will you move back after your mother in law leaves?
Did you ask to eat? Did you go serve yourself? Were they just being passive aggressive rude? I am not certain about any cultural differences that may be tied to Holland versus the United States, but to me, that whole situation just sounds very off. But as an American, I may be quite brash by other country's standards.
I hope things improve for you and that you will let us know some more.