What is the ruling on incest, and are the abuser and fornicator equal in judgment, and is incest considered apostasy from Islam?

Both are grave abominations. However, incest (sexual intercourse with female mahram relatives) is more severe and heinous than harassment of them, and it necessitates a prescribed punishment (hadd), unlike harassment, which requires a discretionary punishment (ta'zir). The hadith concerning the killing of one who commits adultery with his father's wife and confiscating his wealth is disputed in its authenticity. Even if it is assumed to be authentic, some scholars have interpreted it to apply to one who commits such an act considering it permissible.