If you'd have the advice of one who's been through these experiments as long as I have, allow me to suggest a course of action. Don't argue with them. No matter how much their memories conflict with what you know to be true, let them believe as they will for the length of the experiment. You cannot prove that what they remember is false, nor can you return their proper memories before it is undone, so all that would accomplish is driving a wedge between you and them.
What you can do is stay close enough to be available, look out for them in their current state, and be ready for the reactions when the experiment is over. That is when they will be most vulnerable and hurt. That is when they will need you most.
[Video]
If you'd have the advice of one who's been through these experiments as long as I have, allow me to suggest a course of action. Don't argue with them. No matter how much their memories conflict with what you know to be true, let them believe as they will for the length of the experiment. You cannot prove that what they remember is false, nor can you return their proper memories before it is undone, so all that would accomplish is driving a wedge between you and them.
What you can do is stay close enough to be available, look out for them in their current state, and be ready for the reactions when the experiment is over. That is when they will be most vulnerable and hurt. That is when they will need you most.