I have 2 DS's with CF, 1 diagnosed at 6 weeks old and the other ante-natally. In the early days my main priorities were just getting through each day and getting all their treatment done. We were given the CF Trust pack at the time of diagnosis.
I would say at the moment the most important things would be for your friend (and any other family members who will be involved in the care of the baby) to be properly trained to do the physiotherapy which the baby will need to clear his chest twice a day.
Also he will need lots of medication - probably antibiotics and vitamins. He is also likely to need an enzyme replacement called Creon. Most people with CF are unable to secrete the necessary enzymes to digest their food properly. Mine also needed steroids and ant-acids as babies.
It is also important that she knows the CF team at whichever hospital will be responsible for him - in some areas this can be shared between a smaller local hospital and a big regional hospital. Generally speaking the greater the number of CF patients a hospital has the better the care is.
This team should include a Consultant, Specialist Nurse, Specialist Physiotherapist and Dietitian. Sometimes there is also a Psychologist working with the team
The next thing I would want to know about is infection control. It is impossible to prevent all infections. However, people with CF should never mix with each other as they can pass any nasty infections to each other. It is also sensible to avoid people with obvious coughs and colds particularly while he is a baby and hasn't built up much immunity.
Your friend will also need to be aware of any changes which may indicate her DS has an infection which will require different antibiotics. This would include things such as a cough, loss of appetite and lethargy. In this case she would need to speak to the CF team and they will usually do a cough swab to check what the infection is and advise on the correct antibiotic.
Your friend will probably need lots of emotional support, when my DS1 was diagnosed I was utterly devastated and couldn't see how I would ever be happy again. I didn't want to see any one else who had a baby as it all seemed so unfair. If she has any other children it will be hard on them as well - my DD gets very jealous of all the attention the boys get.
Having a DC with CF does change your life and the burden of care can be huge sometimes. It is all very daunting in the early days but this has become our normal now. We have tried to give our DS's and DD as normal a life as possible. DS1 is 7 and DS2 nearly 6 and (touch wood) neither of them have been admitted to hospital since they were diagnosed.
The CF Trust also operate a helpline and Chat Forum which your friend may find useful. We have a big notebook where we jot down any questions we think of so we can ask our CF team.
Sorry this is a bit long but I hope it is helpful.