I appologize for the tough content of the figures below. The numbers are not written in stone, they are numbers that I remember from by anyway blurry hospital stay...
I don't have experience with 22 weekers, but I know about 24 weekers
The most important indicator is the weight. If the baby is a 21 weeker weightwise, he has more chances. At 24w, the baby weight should be around 650g. Generally, they consider babies under 500g not viable. But miracles are possible...
The earliest baby that lived in the hospital where I delivered was 22 weeks, so if your friend's baby has good weight and they can buy them a few more weeks, that would give him more chances.
Now, about chances... for a 24weeker
~1/3 will die in the first 48h
~1/3 will die in the first 2 weeks
~1/3 will survive: 1/3 of these will be normal, with no serious problems (things like astma, eye glasses or ADHD are not considered serious problems), 1/3 will have serious motor problems, or other disabilities but will be able to have a life, 1/3 will be paralized or unable to leave the bed for some other reasons.
Having a 24 weeker that had only 410g (3 weeks developmental delay) and finding out the figures above, we decided that his life quality would be very low and that we want no heroics done on him. They induced me and he died in the uterus at the first contractions, one hour before birth... This reminds me... as the uterus is still small they will have to deliver through a vertical incision. This will cut (and weaken) the abdominal muscles and will prevent her from ever having a vaginal birth.
If possible, encourage your friends to visit a NICU. This might prepare them for what is to come. Its a very tough road that they started on. I don't even know what a win means... they can have a baby that is ok, but the road to get there will be incredibly rough and there are so many dead ends.
But miracles are possible... check this site
I'm so sorry they too have to go through this. Can you imagine what sort of New Year's "celebrations" they had?
Angel stillborn 24w p-e 2/17/03