I think there is so much we don't understand about hemoglobin levels in new babies and what is 'good' or not. I struggle to see how nature can get it so wrong and a cord would need instant attention. No other animals sever the cord before the placenta is delivered.

Both mine were jaundice (mildly) which is linked to delayed cord clamping. As far as we know breastfeeding also increases jaundice, which tells me, some jaundice is normal and to be expected (and perhaps actually a good thing!)

What gestation was your SIL?

Did the dr say there was anything 'wrong' with the high hemoglobin? My understanding was that babies need high levels of hemaglobin because fetal hemaglobin acts differently than adult and helps the transition from womb to world.