I have found, to my continuing consternation, that sometimes we just have to let people have their pain. Even trying to diminish it only pushes the end game out.
This young man has a fantasy which has seeded one in your friend. Though technically both are adults, it is easy to see the childishness of the plan. It will end in pain.
If I was offering advice...it would simply be..."I am your friend and I will be here for you but this will end in tragedy"....
Lenny