Problems I had with this movie. It was unrealistic

I read description of the book on Wiki and it looks like it was very faithful adaptation. So it was the author of the book at fault. Even the whole: "It was the 50-th, things were different back then" dont make sense.

1. I can accept that mother went crazy from the abuse and ran away. Things like that happen. But her 3 adult sisters too? And leave 6 and 8 sister and bother with abusive father? What kinds of monsters they had to be. And none of them thought to take her with them? They just left her to be beaten up? And then brother left? To go where? What did he eat, where he lived? He was a child.

2. So this mans whole family just dissapears and no one in town asks where they are? No police, no one? They didnt wonder if he didnt kill them all? Which brings to conclusion that mother could have just kill abusive husband and no one at all in that town would question what happened to him. She could even say he ran away and left them and it would be a reasonable explanation no one could overturn.

3. Where did father work? No one wondered when he didnt show up and went missing? It seems everyone in town knew that there 8 years old child that lived alone in the mush unsupervised and no one cared. No police, no one. And she frequently came to town. And she lived from the gardening and trading fresh mussels and smoked fish for money. Thats where whole food and all stuff came from for 10 years? She is like female-tarzan. I’m surprised she didnt learn to read by looking at the letters in books like Tarzan did. ))))

4. Bering literally she-Tarzan she behaved like skilled and wise teenager when come to dating those two college boys. Instead of being naive and not knowing anything since she lived alone in the woods her whole adult life.

5. For living alone she looked so clean and elegant all the time.