I don’t think it’s fair to characterise her as a repeat offender: some children are more susceptible to headlice and find it harder to eradicate them. All the olive oil, tea tree, Child’s Farm, snake oil, etc in the world didn’t work on DD and we were at her with the nitty gritty daily, through tears. We even had headlamps. Those little bastards have evolved to survive. What eventually worked for us was an expensive visit to a private nit specialist in London who literally vacuums the fuckers out of the hair, followed by a section by section combing under “hospital emergency surgery floodlights” lighting. It took hours and she still had to have a second visit because brand-new lice eggs are invisible to the naked eye. There were three when we returned. Then they were gone (sadly not forever but she did grow out of being their favourite playground and we also keep her hair pixie cut short as a preventative measure).
There’s no evidence to say this mum is repeat texting OP out of blame; she could well be hoping to prevent sharing the misery. DD and I were in tears daily for months and we spent 90% of our free time relentlessly combing and applying every potion under the sun.
Eradicating headlice as a thing isn’t so easy either: they lay invisible eggs (to start with), glue them to the scalp/hair shaft, the lice crawl at 23cm a minute and run from movement and light, they’re born sexless and pick a sex later on, so you only need 2 eggs leftover to start a colony, and the females only need to mate ONCE to then lay 10 eggs a day for a month. They also evolve to match hair colour to be harder to see, so if you see a blonde louse on dark hair or dark louse on light hair you know it’s a new passenger picked up from a play date rather than a locally born and bred one. (I did a lot of late-night doomscrolling during our unfortunate lice months.)
The fuckers have also all evolved to be immune to all the sprays and lotions: we found that they’d be stunned into submission from whatever stinky potion we applied, but it wouldn’t actually kill them. If anything, they’re getting harder to eradicate. And with the cozza living more people are going to rely on cheap conditioner and a comb than invest in two doses of Nit Begone or whatever; few people are going to be able to afford the vacuum treatment.