Hey there. My daughter is 25 months. She was about 20 months when she was diagnosed with a severe peanut allergy, and prescribed the epipen.
We knew she was allergic much before this time, but we didn't know how allergic she was. When she was 12 months, her dad was eating a pb&j sandwich. She wanted some, so he gave her some of the bread with a tiny bit of peanut butter on it. All around her mouth broke out. Well, we were suspicious, but not certain what that was. So, the next time she was around peanut butter, we let her try it and the same thing happened. After that, we realized we should probably keep her away from it. Well, on Easter we went to a cousin's house for egg hunting. The eggs had those little chocolates that are half chocolate and half pb. My daughter took a bite before we realized what it was, and she began to break out. This time the break out was worse. Her whole face had hives. Even her eyes were all red. We decided to go home and get her some Benadryl. On the short drive home we turned around to find her unresponsive. We called her name with no response. We lifted her arm only to watch it fall. Her tongue was hanging out of her mouth and she was drooling. We were about to lose our minds. Finally, I jabbed my fingers down her throat and she repsonded. After that, she was okay. We knew then that she was in trouble when it came to peanuts.
The thing about peanut allergies is that it is said that the more exposure, the worse the allergy. Some people are exposed so much without being aware and then get to the point where they get sick just smelling it. So, tell your friend that he will definitely react if he ingests it.
ALSO, being that peanuts are legumes, tell your friend to watch out for other legumes. We found out last week that my daughter is also allergic to lentils and pinto beans. The reaction was not nearly as severe as the peanut reaction. I don't know if she is allergic to all beans, but I don't really care to try anymore.
I am sorry for your friend. I understand her fear. I had a horrible and very real dream about my daughter and her allergy. It's very scary, but I think as we get to understand and know the allergy better, we will find a little more comfort.