I just had my son at 30 weeks. I was fine one moment and within 15 minutes in labor and in the OR being delivered. They careflighted my son to another hospital with a more intensive NICU so I had to wait 3 days to even see him until I was discharged from the hospital.
Your friend's little girl has an excellent chance of growing up to be healthy and normal, but there are alot of things to consider along the way, and if there are issues, some may not arise until the little girl is 2 or 3 even older. There were a few babies as young as 24 weeks in there, barely at 1 lb, and they did fine.
My son stayed for 5 weeks in the hospital. I didn't get to hold him for the first 10 days due to an IV in his belly button. Once that came out I could hold him and they highly encouraged it, as it kept him calmer than laying in an isolette.
Everything is monitored constantly so keep that in mind. Jacob (my son) was weighed twice a day, and slowly weaned off the meds and monitors one at a time. He made progress but would have a day here and there where he regressed a bit. It is to be expected. Seeing your baby hooked up to so many machines and monitors is a little frightening but you get over it pretty quickly. The biggest obstacle to overcome is the immaturity of the lungs. The shorter the timespan she is on a ventilator the better. Fortunately Jacob got moved to CPAP after just 24 hours on a vent.
Once they have matured to the point they can breathe on their own (even if it is with a cpap) the stress on their bodies is significantly lowered.
Being in the NICU they did weekly brain scans to check for any signs of bleeding in the brain, which they did not detect for Jacob but it is very common in preemies, which is the main cause of having issues with retardation, and other mental issues, as well as some physical limitations. These are the things that won't be noticed until a child fails to hit milestones along their development.
Keep in mind for your friend that even when they discharge her daughter to come home, she will still be in "newborn" status for quite some time, and that she will be slower to hit milestones than a regular newborn. She should hit them by her "adjusted age" which is the age she should be had she been born full term. Jacob is almost 3 months old now and is now starting to have a little bit of a personality, picking his head up and turning it from side to side, and being much more "wiggly". He does like his snuggling too though
Try to be supportive of your friend if she is tired, stressed, sleepless, and overall short tempered. It is a tough thing rearranging your entire life to accomodate specific schedules at the hospital, meeting with doctors, etc.
Advise her to not feel in such a rush to get her daughter home though. Let her take all the time she needs in the hospital to make sure that her little body is really ready to handle the outside world. We made that mistake and it nearly cost us his life. Jacob had made rapid progress and they were considering letting him come home, but our hospital does a "rooming in" night prior to discharge where we stay in a room with him just as if he had been born normally. That day the doctor decided that maybe we should just give it another day or two since Jacob was only 34 weeks at that point. I was upset but not alot I could do about it. That night, Jacob stopped breathing and had to be stimulated to breathe again. Had he been rooming in with us he would have died right there in the hospital with us instead of having the nurses alerted by his apnea monitor. He ended up staying an additional 6 days.
Jacob has now been home for 6 weeks. We do not take him out much, and nobody gets to touch him or hold him unless we agree and they do a good scrubbing of hands and use hand sanitizer. What might normally cause a mild fever or a runny nose in other infants can land Jacob right back in the hospital, as his immune system is still somewhat compromised, so let her be overly cautious about who that baby comes in contact with. Don't be offended if she doesn't want anyone coming over or around for awhile. The hospital will likely tell her to be that way. Mine did.
Sorry for the long post, but feel free to pm me with more questions or anything.