Sodomy does not prevent marriage to the sister of the one with whom it was done
23-1-2014 | IslamWeb
Question:
Assalaamu Alaykum,
Is it permissible for one to marry a girl with whose brother he practiced sodomy fifteen years ago, and then repented and showed regret for what he had done when he was still young?
Give us a Fatwa in this respect. May Allaah Bless you.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
No doubt, sodomy is one of the gravest major sins and one of the most grievous misdeeds, and its perpetrator deserves stoning to death if he did so while being mature. It was narrated on the authority of Ibn ‘Abbaas 
that he said: "Whomever you find doing what the people of Loot (Lut) did, then, kill both the doer and the one with whom it is done." [Ahmad, Abu Daawood, At-Tirmithi, An-Nasaa‘i and Ibn Maajah]
But even, this does not prevent marriage to the sister of the one with whom it was done; he has the right to marry her since she is not included in the women whom Allaah Forbade for marriage in His statement (which means): {And do not marry those [women] whom your fathers married, except what has already occurred. Indeed, it was an immorality and hateful [to Allaah ] and was evil as a way. Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allaah Is ever Forgiving and Merciful. And [also prohibited to you are all] married women except those your right hands possess. [This is] the Decree of Allaah upon you. And lawful to you are [all others] beyond these…}[Quran 4:22-24]
She also is not of those forbidden (for marriage) by the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, in his statement: "Suckling relation forbids what corresponding blood relation forbids." And: "One should not combine in wedlock a woman and her paternal aunt, or a woman and her maternal aunt." [Al-Bukhari and Muslim]
The questioner has to persist in repentance and regret the sin he committed.