Very hot water (60 degrees C or 140 degrees F) kills head lice adults and nymphs, if applied for at least 30 seconds.
A test of motherly love: to comb through her child's head-lice-infested hair every night for two weeks.
A test of fatherly love: to vacuum and iron the mattresses and floor in the bedroom of the head-lice-infested child every night for two weeks. Add to that doing humongous loads of laundry on HOT and drying on HOT. Add to that earning the money to pay for all that water and electric use.
Do not ask me how I know these things.