Sometimes Christians are seriously oppressed by demons, this means the demons possessed their souls (this is not real demon-possession because this happens with unsaved people when the demons possess their spirits. In such cases, the demons are almost in total control and these people must be assisted by an exorcist. They cannot help themselves and they do what the demons want them to do.
Demons possessing Christians’ souls are not in total control but they do get their way quite often. Such Christians struggle seriously with sinful issues. Although it is not a real possession, the demons must be cast out by an exorcist.
Then you get people, Christians and unsaved people, who are merely influenced negatively by demons (on a continuous basis meaning the demons are constantly surrounding such people or always with them). This is when the demons did not possess their spirits (unsaved people) or their souls (unsaved people or Christians) but are harassing people, tempting people, and urging people to do what they want them to do. In such cases, these demons must be chased away from these people. The Scripture supporting this is found in Mark 16:17-18 (Geneva Bible) “And these signs shall follow those who believe: In My Name, they shall cast out demons, and shall speak with new tongues, “and shall take away serpents. And if they shall drink any deadly thing, it shall not hurt them. They shall lay their hands on the sick, and they shall recover.”
Take note that they should “take away” serpents as correctly translated in the Geneva Bible (by the way, the Geneva Bible is by far the most correct translation ever published) (not “take up” as incorrectly translated by other translations). Read more about this at this links: White Cover Red Stone Dream
About your friend, even though she had the dream, it depends on whether she has the faith and spiritual power to do it. God revealed it to her but you will have to ask her whether she can or not.