Since I have no idea why they started your friend on the nipple shield in the first place I'll tell you my story. I started using one at 4 weeks because my dd had done such horrible damage to my nipples with a bad latch (a REALLY hard to identify bad latch). I was in such pain, bleeding, scabs, you name it. (I should have gotten help MUCH sooner) The nipple shield really saved our breastfeeding relationship and I was soooo grateful the first time the lactation consultant put it on and I could nurse without cringing and crying. Well, the theory was to use it until my nipples healed and then to stop using it. Easier said than done. We are STILL using a nipple shield at 7 mos.
Luckily your friends baby is still really young and not stuck in the habit yet. I'd recommend having your friend use the nipple shield initially each time she nurses, until the milk lets down, then take baby off and relatch without the shield. Of course, that really is assuming there isn't some other problem. Actually, scratch that... I'd have her see a different lactation consultant to make sure the baby latches on well and then get rid of that shield altogether. And more than anything... tell her NOT TO STOP TRYING. She can do it! And good for her for even trying when she doesn't come from a family that's very supportive of breastfeeding. Have her call her local LaLeche League... they can give her tips and give her much needed support. Weaning from the nipple shield takes lots of patience but is better done sooner than later.