We ask Allaah to grant your mother quick and full healing by His Leave and to decree for her and you reward, patience and steadfastness.
We do not see anything in your question that would make us say that you should not go to that woman who treats people with ruqyah. It says in the question that she does ruqyah by reciting Qur’aan, and she uses blessed oil (i.e., olive oil) and ‘ajwah dates which protect against poison and spells by Allaah’s Leave, and the fragrance of rose water which gives one strength to resist witchcraft and hasad (destructive envy); some of them also use ‘ood (aloeswood) and bukhoor (incense) to achieve the same purpose. All of these are things that are acceptable in sharee’ah in sha Allaah.
But what we see here is the use of salt which is sprinkled in the house, and we are afraid that this idea may have been picked up by some of those who do ruqyah from the myth or belief of the common folk that salt wards off the evil eye and so on.
We asked some of those who do ruqyah about that and he said that salt has no such effect, even though some people use it.
What we advise you to do is to be fully aware of what words and recitations she uses in her ruqyah, and if she uses anything other than the Islamically acceptable words such as dhikrs, du’aa’s and verses, such as things that cannot be understood, or you have any doubts about her, then hasten to ask her about what it means, and ask knowledgeable people about her. Many of those who treat people with ruqyah pretend to be reciting Qur’aan to fool the listeners, when in fact they are using sihr (witchcraft) and trickery and using hidden words which they say or write in order to harm the sick person so that he will carry on coming to him and giving him money.
And Allaah knows best.