Here’s an ethical issue and Jewish source response:

Case

Susie’s good friend Jane accidentally finds out a secret about Susie’s fiance Judah: he has a debilitating medical condition, which will result in his death within two years.  Judah has not told Susie, his-bride-to-be, about his condition.

Answer

Should a person reveal important, confidential information to a friend about her, if the fiance himself did not reveal it?

[a] In general, a Jew may not reveal information that is told to him or her, even if the provider of the information did not request that it be kept secret (Yoma 4b).  However, if the information will potentially save a life, then a person is obligated to reveal such information, even if sworn to secrecy (Shulchan Aruch, Choshen Mishpat 426.1).  The values of trust and saving a life have to be weighed carefully here.

[b]  In the situation presented, which deeply affects the lives of the people involved, the Chofetz Chaim (Shemirat haLashon, 9:2, example 3, paragraph 7) states that the laws against speaking lashon hara (evil talebearing) do not apply.  Therefore, Jane should tell Susie about Judah’s debilitating condition, but only if four conditions are present: 1) the danger to the person (Judah) must be real and imminent.  If Judah’s disease would cause his death only thirty years later, then the information may not be revealed;  2) One may not exaggerate the information while disclosing it.  Thus, Jane cannot say that the disease will kill Judah within six months; 3) The motive for revealing the information must be pure, i.e. to help the receiver of the information.  It may not be undertaken for personal gain or for revenge against a person one dislikes; and 4) The information must greatly affect the relationship.  If the friend knows in advance that the couple is so much in love that they will surely marry anyway, it is forbidden to reveal such information.  

It should be noted that if the person can accomplish the same goal without having to break a confidence, then one may not reveal such information in that case.

Joel Grishaver, “You Be the Judge 2”, pgs. 45-46

Used with permission from Joel Grishaver