They could have been referring to the scenario that the letter stated NO member of the family was to be questioned w/out a lawyer present. Maybe they asked her about it b/c they were questioning her about something earlier on, (considering KF & MF believed these people to be on their side), so it was a casual conversation and he asks her if it is necessary to have someone present and she was just like "Nah, it's cool, I will talk to you."
As for the legal advice - it sure seems Scottie boy had never seen something like this before and didn't know proper protocal, or didn't know if he had to actually follow the advice on the letter. I would bet the forgotten advice was to CYA and have someone present when speaking to the Foxes! If the person cannot remember what advice they gave to him specifically, I am curious to see how they would answer the question of "Well, if you were to be approached with a letter like this, what would be the standard advice you would give?"