Things happen, and killing a human being is not a just a peccadillo. But things have been done.
There is no better than to maintain as much as possible mindfulness, train the mind and do meritorious deeds. Focus everything on Metta Bhavana and keeping precepts eager from a mind of metta. Being aware that things may ripe and not engaging to fight against things.
Its also good if such as a forgiving ceremony for her former child is made. Such declaring of the misdeed and closure should come from heart and should have an understanding for the "victim" and not be made just to protect one self. So one must see ones fault accept the results and act simply as an obligation for the victims welfare.
Atma is not sure if there are people who are trained and taught in such as "family constellation", which, if the teacher is a good one, helps a lot since he/she would help that such things are not done just on the surface but form heart to heart which gives one the needed release to walk on.
In the same spirit, one should not do such things as having the intent to dispel or harm or kill spirits. That would make things even worth. So she would do good NOT to seek and wish for any exorcism. That is like to kill again and has not confession and accepting of ones misdeed as a drive. So she should work firm to see the transgression and simply act like that. But also, it does not make sense to fall into "I am bad. Punish me" thinking. That is also foolish. What has been done, has been done.
Its good to seek good teacher in Dhamma who explain and make here Dhamma understandable but never ever hire people to fight or even hurt and kill spirits. Seek for people who are able to explain what and how one self should act and practice, so that there are no causes that one gets hurt.
For giving spirits no opening, there is nothing better as mindfulness, being mindful and never lose earthing. One being aware does not give his body. Mind and body needs to be firm together. Sometimes such as physical exercises maybe even such as yoga, are good that people get aware of there body. And again: All training, all actions, are not meant to fight others or to harm them but with the purpose "May I not harm any being, may I am always firm in my precepts so that no beings is caused harm by heedless actions of mine"
There might have been no fault by the monk aside that he just did something that they wanted. Even he canted such as a protective paritta, when such is used with aversion mind it turns out even more worse. So its needed that she learns about the Dhamma and why metta is useful and how the mind have to be that it is a protection. Atma thinks even to make a month a retreat and been taught by monks and nuns would be good, taking on 10 precepts. Maybe in the nunnery of Na Uyana Aranya. It makes less sense to approach normal village monks and those making a living with spells and services for laypeople. They make it even worse.
(Note: this answer has not been given with the agreement to be means of trade or the purpose of/for trade and/or keep people trapped and bound. How you handle it lies in your sphere, but does not excuse the deed here either.)