Anulling a civil marriage

Igros Moshe (E.H. 4:52) impotent husband. wife complained that she married a man who was impotent and he had the problem even prior to marriage and the condition was incurable. There are reasons to believe the claims are true and she has remarried without a get and had children from the second marriage.  The first marriage was annulled in civil court when a doctor under oath said she was still a virgin and had never had intercourse. The first husband was told to give her a get but he refused unless  he was given a large amount of money which was not able to provide. . She later remarried to a second man in a civil marriage  and had two sons and a daughter. Her parents testified before beis din that their family doctor,  who the beis knows to be  frum was also the doctor of the first husband from his youth, that the first husband was always impotent and was not fit for marriage and that if he had known that he wanted to get married he would have advised against it. While this doctor is no longer alive, a second Jewish doctor who has testified that the first husband was always impotent. The first husband has remained silent. The issue now is the status of the children and whether they can marry Jews.  I have already explained  and ruled in Igros Moshe (E,H. 170) that if there is a major deficit such as impotence which involves the bases of marriage that there is no need for a Get even rabbinically. So in this case, if all the facts are unquestionably true and she can not obtain a get and especially related to the status of the children. I ruled after a number of years similarly in a case where the husband was a shoteh (severe mental illness) even prior to marriage which is also clearly a great deficit [mum gadol] as noted in Yevamos (112b) that you don’t  marry a shoteh because of the rule that a person does not dwell together with a serpent in close quarters.Therefore she should be allowed because of kiddushei ta’us (mistaken marriage) if it is impossible to obtain a get.