Tell him he needs to burn their nail clippings, too. And make sure that they don't leave footprints in sand or mud, because sand/dirt from those footprints can also be used for bad magic. He should never let anyone take photographs of them, either.
Hair and disposable tissue paper are not to be disposed in the toilets right?
My SO always ask me why don't I throw the hair from my brush into the toilet, or the paper tissues, and I'm always telling him that's quite a stupid thing to do (I'm not a 100% sure about it but hey, you never know right).
Hair should be burnt. Its the only way to prevent misfortune and sickness.
(No, not really, but a friend of mine burns all of his children's hair because he, as an educated, mostly unsuperstitious man, truely believes his younger brother got pneumonia because a family member cute off some of his hair and "worked bad magic" over it. So as much as possible all of his kids' hair gets burnt when it comes off them. I personally throw mine out in the trash.)
(Why, yes, I *DO* know too much about ritual magic!)
He does burn their nail clippings. And any cloth or bandage that they bleed on. Photos don't seem to bother him and I have no idea about footprints.
Incidentally, his grandmother talks to spirits and predicted the day my stepdad would die. As in called me up out of the blue, told me she was "[ x ]'s grandmama" and that she needed to tell me that my stepdaddy was going next week on the 13th, and to be sure to kiss him when he "left" which was strange because he was bedbound.
He was taken to the hospital for a heart test and I did kiss him goodbye but I didn't think about what she said until the next day when I got the call that he had passed.
She also predicted the genders of babies. And has never missed. But i think she just knows how to feel certain "areas" because she makes her announcements after the mother is 5+ months along and after touching all over the belly and rubbing.
Still, since his grandmother told him the burning hair/nails/blood thing, I suppose i can't blame him for doing what she says. It certainly can't hurt and she
is almost certainly right.