No big deal, it happens.
After a summer of camp, I feel like the lice expert! I learned that the lice are attracted to the smell of sweat. So try to be sure she keeps her hair clean moving forward. If she plays sports or it is still hot outside, she should shampoo.
They need the warmth of our scalp to lay their eggs. So they like to stay inside the hair near the scalp, but will transfer to another head if there is hair near by to transfer to.
He needs to go to the drugstore and buy some lice shampoo. He should follow the instructions on the package. It is very expensive, so the store brand will work just fine.
While she shampoos, he should change the bed sheets and vacuum, starting with her bedroom. I liked to put double pillow cases on my pillows. So the opening to pillow case number one is inserted into pillow case number two.
If she can handle the heat of the hair dryer, they cannot take that heat and will die. It is pretty warm though.
He should vacuum the whole house including the couch. He can store her comforter and stuffed animals in plastic bags for 7 - 10 days. Ten to be safe.
While the shampoo is in her hair, she should use the little knit comb provided. Also, shampoo the brushes and combs. I would wash them all and use one brush and place the rest in a plastic bag for 10 days.
Since there is probably a situation in the classroom, she should wear her hair braided or tied up to keep them from transferring back to her.
Remind her as she hugs her friends to make it quick and keep their hair from touching each other.
Last weekend we went to a birthday party at the facility she went to camp at. I swear she kept getting head lice from the rock climbing helmets. After my big fit over the summer, she took her own bicycle helmet to the party. They climbed the wall and she was the only one with her own helmet. My husband was a little uncomfortable, so he kept taking the helmet back to the car...while I could care less because I was not picking lice out of her head one more time. Her best friend asked if she could borrow her helmet because there weren't anymore and I said, no I am sorry we don't share head gear. Just then, she took both hands and scratched her head and I thought...that is why.
Edit: In response, the heated hair dryer does work, as I have done it, with out chemicals or any other treatment. They were dead. If it was a hunch, I would say it may work, but I have done it. Maybe it didn't work for that other mom, which is too bad. As well, lice like hair, clean hair, dirty hair, oily hair, any type of hair, however, they are attracted to the smell of sweat. Something has to attract them so they know there is a new place for them. They don't fly, they crawl. They like to stay close to the scalp, so when there is a new scent, I am certain they move away from the scalp of their current home and move to the next. I asked my pest control man and that is what he said. It seems to make sense, as if you read about them, they move from head to head and more common in children, yet not prejudice by any means. So moving forward, it is a good idea to keep the hair/scalp clean after playing or activities that make you perspire. I live in the desert, so we are sweaty all summer long. As well, my daughter is in sports, so again, she is always drenched in sweat. At this point, she is not in camp where they ran around all day long, played outside, and sat closely in multipurpose type settings on the floor. She has been clear since the start of school. I believe that is due to the preventative measures, as well, she has to come in contact with them and hasn't.
Everyone has their own theory or method on what works. You will find all sorts of suggestions. What I have shared with you has worked for my daughter. In any event, it is not a fun situation.
Wish your X luck.