The note from Brother Hoberman is a paper note in Fallout 4.
Location[]
It's carried by Mother Isolde.
Transcript[]
Mother Isolde -
We have found the cave where this "Virgil" resides, southwest of the crater. It is defended, as you suspected.
[illegible] not act against him until we [illegible]
Related quest[]
Notes[]
The transcript from the game files provides a full version of the partially torn note found on her body which reads:
Mother Isolde -
We have found the cave where this "Virgil" resides, southwest of the crater. It is defended, as you suspected.
We will not act against him until we have word from you, or a sign from Atom himself.
Brother Hoberman