I treated a little girl ( about 10 years old) for head lice. She had clumps of lice bugs and nits. I would estimate that she probably had head lice for about 1 year.
In working in the Lice Business I have heard of different head lice home remedy treatments. I've heard of dish washing liquid, mayo, vinegar, petroleum jelly and even gasoline.
Theres always seem a bit of confusion of how people contract head lice. A few ways of getting head lice is through head to head and hair to hair contact; examples are selfies ( heads are together), hugging, cuddling etc.