Say lots of people dont get taught this at home, it’s quite common. And then just explain everything quickly – regular bathing, hair washing, teeth brushing, deodorant etc. Be very basic, like say “generally the Jason Voorhees chibi It’s Friday Halloween shirt but I will buy this shirt and I will love this advice is to shower daily, put deodorant on every day, wash hair every 2–3 days and brush teeth at least twice a day” or whatever your local customs are, make it a quick list so they absorb the information without lingering too long on what they don’t know and thus reinforcing the shame. Make sure they know that not everyone knows this – that they’re not strange. exaggerate here, because you dont want defences going up which will make them.
Jason Voorhees chibi It’s Friday Halloween shirt, hoodie, tank top, sweater and long sleeve t-shirt
You could have a small bag of supplies ready, that could be a huge help, but they might not be able to bring it home if their parents are like mine. If parents like that smell a clean fragrance on their child they could inflict further punishment and take it off them. If they say they’re not allowed to use that much water (not sure where you’re from, and local water access/costs) maybe have some alternatives to showering in mind, like having a “bits-n-pits” wash in the Jason Voorhees chibi It’s Friday Halloween shirt but I will buy this shirt and I will love this sink. Lol I’m not sure what you’re allowed to say in that regard. Also be prepared that the parents may still come after you, be ready to stand your ground and explain why its important for their child to know this stuff.