Folklore has it that seal paste does not like metal; I ignore the scientific reason behind this, if there’s one. Bone, ceramic, or wooden tools can be used all right.
Your friend’s seal paste indeed looks quite dry. It’s hard to say from the photo if it is still usable, but she can try it. To take better care of seal paste in the future, note that it’s not just a stamp pad. To begin with, it should be stirred every few months. The method of stirring is to roll the paste into a ball. When applying it on the seal, tap the seal gently on the surface of the ball. I looked up a couple of videos for you (not mine):
Applying on a seal: https://www.youtube.com/watch?v=2yA_wNKHG5w
You can find more by searching for “攪拌印泥”. To store seal paste, I suggest wrapping the entire porcelain box in cling film.
The traditional oil to use is castor oil, try just a couple of drops and let it absorb before stirring as described above using bone or plastic spatula. The reason not to use metal is if the paste is made with genuine cinnabar (sulphide of mercury) it will dissolve a little of the other metal in time, cheaper pastes, such as those that come in tins, are now made with synthetic pigment.