Answer
(Fatwa: 1917/1356/L=1432)
The nikah of a woman is lawful with a eunuch if he is male; likewise it is valid with castrated male and impotent person. However after three talaqs and after passing iddah, she will not be halal for the first husband until she marries other man and he has intercourse with her and then gives her talaq and she passes her iddah. And it shall not be lawful for the first husband to marry her without fulfilling the above mentioned conditions.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband