If you want pal, I can talk to her by phone. Send her my number if you wish, i can PM it you.
PsA is notoriously difficult to diagnose, kudos to her hubby for sussing it out before her GP. To be fair to GPs they receive very little training in this area as it is highly specialised.
I totally appreciate why you are scared for her, I remember being diagnosed and feeling it was the end of the world. Fortunately medical advances means PsA is treatable. The problem is because we are all different at the moment it is a case of trying different treatments until you find the one that suits you. I was speaking with a researcher yesterday on this subject and there is research going on into genetics to see if they can work out from our genes which treatment will work best.
PsA is a strange condition, you can have "flares" and then it can settle down and you can return to almost normality, then flare again. Some people work out what triggers these "flares" simply by trial and error. Doing things like cutting out dairy foods, stopping drinking, giving up smoking, not eating tomatoes, the list is endless.
If your sister has any questions I am always happy to help as much as I can, if I cant help i can signpost her to places and people who can.
As for you pal, try and be understanding, be there for her and realise there can be deep psychological impacts attached to PsA.
good luck mate