I understand where you're coming from, I've had clients message and ask can they buy a box dye etc... I've also had clients send pictures of their kids where the parents have shaven the kids hair clean off.
By no means will they ever be able to recreate what we create with our scissors.
But if it saves the poor children from getting a skin head, then maybe just offer basic advice, like reccomend a 3 on the sides and Tim the top for example or even using a larger guard on the clippers for the top, something that isn't too drastic, something that will help keep their hair looking tidy, but still something that won't take us weeks or months to correct.
It's such a difficult situation and it's hard to have the right answer. I'm even sure if there is a right answer in these situations....