Impurities

A few days ago I had a very good chat with my mum about impurities and how it transfers from one objective to another. She sounded like she understood that impurities transfer. I fell satisfied. Today I saw her changing the nappy of my nephew. She didn't wash her hands and she wrapped the baby in one of her scarfs. I doubt whether her she will wash the scarf or not. If I tell her wash it, she might say yes or even wash it but I think when I am not home how they will deal with it. She will be using all daily objects which I use when I come home. I can't avoid touching them. What should I do? She thinks I have OCD. She doesn't care I think.