U.S. immigration law provides help for people who have been abused by their US relations.  The Violence Against Women Act (VAWA) applies to husbands, wives, parents and children and allows the abused person to obtain their green card without the involvement of their abusive US relative.

When the foreign-born relation of a US citizen (and in certain cases, permanent residents) has experienced extreme cruelty and abuse at the hands of the US citizen, VAWA allows the foreign-born person to file a petition by themselves.  When the petition is approved, the person may then apply to adjust status.  If the relative of the self-petitioner is a US citizen, then the self-petitioner may apply to adjust status at the same time as the self-petition is filed.