Ginger, no I haven't been on the end of a decision regarding allergies, but I have worked in health care and know people with allergies, so understand the problems. I have no idea how this cabin crew member reacts, but if it's anything like my daughter, her eyes will get sore and water, and nothing more. (not a peanut allergy) It's certainly not life-threatening, but quite definitley uncomfortable. The other allergy my daughter has makes her breathing "tight", but again, not life threatening in any way, more like hay fever.
We carry a fair few passengers who we know have severe allergies and carry an Epipen with them. We are told at the pre-flight breifing and we simply make a PA asking passengers not to eat any products containing nuts. Fortunately we don't have stroppy passengers who can't live without nuts for a few hours.
I really don't see the fuss in asking people not to eat nuts for a few hours. Would the friend have complained if he'd been told a passenger had an allergy to them? No doubt the crew member has been passed fit to fly by staff health, as the last thing she'd want is to put her own life at risk. I hope she asked the friend nicely, that of course makes all the difference.