The ruling on marrying a woman when her mother's husband acts as her guardian

Question:
Here is a long written message, sent in the colloquial dialect to the program from Jeddah, by one of the sisters. She indicated her name with the letters: (F. A. H. N). Our sister has a case that filled a full page, which she summarized in the following points:
First: Her mother’s husband was the one who took charge of her guardianship when the contract was written, while her maternal brother was present at the marriage.

Answer:
Neither of them is a guardian, neither her mother's husband nor her maternal brother. Neither is a guardian in marriage. Her guardian in marriage is the 'asabah: her father, if he exists, then her son, if she has sons, then her full brother, then her paternal brother, then her full brother's son, then her paternal brother's son, then her full paternal uncle, then her paternal uncle, and so on, the closest to the closest.
If she has no 'asabah relatives, then her guardian is the judge, who marries her off, because he is the deputy of the Sultan. The Prophet (peace and blessings be upon him) said: "The Sultan is the guardian of the one who has no guardian."
As for her mother’s husband, if he is not her paternal cousin, her mother’s husband, if he is not her paternal cousin, is not a guardian. Likewise, her maternal brother, if he is not her paternal cousin, is not a guardian.
As for if her mother's husband is her paternal cousin, and there is no one closer to her than he is, then there is no harm in his marrying her off, because he is a paternal cousin, because he is an 'asabah, not because he is her mother's husband.
And likewise, her maternal brother, if he is her paternal cousin, and there is no 'asabah closer to her than he is, may marry her off, because he is a paternal cousin, not because he is a maternal brother.
And if no one is found in that position, then she returns to the judge, to the Sharia court, and the Sharia court takes charge of that, either the judge takes charge of it, or the judge appoints a trustworthy person to do it, yes.

The presenter: And in the case where the contract took place and he did not possess any valid quality?

The Shaykh: It is annulled, the contract is annulled, and it is renewed anew in the Sharia manner. It is annulled and renewed, and the husband refrains from approaching her until the contract is renewed, if he has the desire, and she has the desire. If they agree, the contract is renewed.

The presenter: She also says: Her mother’s husband worked to have her divorced from her husband, and he denied most of the mahr (bridal gift), and she was divorced because of him?

The Shaykh: This is to the court, this is to the court, yes.

The presenter: He married her a second time, and he was the one who took charge of her guardianship while her maternal brother was present?

The Shaykh: The hadith is mentioned in this, and that it is not valid from him or from her maternal brother, except if they are her paternal cousins, and there is no one closer to her than they are, then it is permissible for the mother's husband to take charge of marrying her off, if he is her paternal cousin, and there is no one closer to her than he is. And likewise, the maternal brother is permissible to take charge of marrying off the maternal sister if he is her paternal cousin, and there is no one closer to her than he is.
And if the contract is completed with the mother's husband, and he is not a paternal cousin, or with the maternal brother, and he is not a paternal cousin, or he is a paternal cousin, but there is someone closer to her than he is, then it is annulled, and it is renewed anew if they desire to renew it. If the husband and the wife desire it, it is renewed, yes.

The presenter: May Allah bless you, and may Allah reward you with good. So, is the contract considered invalid in the state mentioned, if it does not possess the correct attributes?

The Shaykh: Yes, yes.

The presenter: And she must rewrite the contract anew?

The Shaykh: Yes, with her closest guardian.