I wouldn’t wish this to sound unsympathetic - though I’m sure it will.
She can run, she wouldn’t have passed out of Phase 1 if she couldn’t. If she now finds she can’t pass it’s either because because she has an injury or because she’s not putting the effort in to maintain that level of fitness. Now, I will say that while I appreciate that we all have our own talents and abilities, and that what one finds easy another won’t and vice versa, I do however lack sympathy for those that can’t pass their RNFT. The standard required isn’t high - if I can run 2.4k in under 11 mins at 48 then I fail to see why someone 30 years younger than me can’t.
I fully accept that she may not like running, I don’t. But I still do it, albeit as little as I can get away with. I keep my CV fitness up in other ways, for me that’s predominantly cycling.
So she needs to do two things; find a method of exercise that she can at least tolerate if not enjoy, and put in real effort. And I say that as someone who works in a Phase 1 training environment. I see young men & women failing or struggling with their phys, not because they can’t do it, but because they’re not pushing themselves. At the risk of sounding all ‘in my day’, too many think that being out of breath is having reached their limit. And I’ve seen plenty of those on RNFT remedials still not passing. They’re attending every remedial session, but not pushing themselves, not trying hard enough. And so aren’t getting any fitter.
As I said, it might sound harsh - but sometimes reality is. She’s causing herself (and you) unnecessary stress - not to mention putting her career at risk. If she wants that monkey off her back she needs to grip it.