MamaMary, 12 per cent loss of weight is usually considered to be a sign feeding is not as effective as it should be. The usual 'cut off' is 10 per cent. Sometimes, with a bigger baby, or with a baby who is clearly feeding well after a slow start, it's not something that needs to be fixed, but more usually, the response of the midwife should be to fix the lack of milk super-quick; newborns need to feed, obviously, and too much weight loss can mean the baby can become seriously ill (dehydrated, low blood sugar).
In some circumstances, formula is needed while at the same time working on the breastfeeding, so the mother's choice to breastfeed is supported, so she can drop the formula once the baby's weight and health are normal. It does not have to mean the end of bf.
You can't really tell what's going on - maybe this baby was seriously compromised and the midwife reckoned top ups at every feed were needed. On the other hand, maybe a smaller amount of formula (ie not at every feed) would be sufficient.
Whatever....your friend also needs to have been given support and info on protecting her milk supply through this crisis, if she plans on returning to full bf. Maybe you can tactfully ask if she has been given this sort of support alongside the advice to top up.