Is a triple divorce considered valid if the marriage was conditioned on a future event (the sister's recovery) and the condition was not met?

If the legal marriage contract has not been concluded, then an oath of divorce is null and void, with no effect. However, if the contract has been concluded, and you swore by triple divorce and then broke your oath, the prevalent ruling is that she has been divorced from you thrice, and has become irrevocably separated from you (baynunah kubra). She is not permissible for you again unless she marries another man and he consummates the marriage with her, and then he divorces her or dies. Some scholars hold the view that this divorce does not occur if it was intended for emphasis or threat, and you are bound by an expiation for breaking an oath (kaffarat yamin). However, if you intended to effect the divorce, only one divorce occurs, and you are permitted to marry her again with a new contract. The prescribed oath is to swear by Allah the Almighty, and swearing by divorce is among the oaths of the dissolute.