I don't quite agree. "A quelque chose, malheur est bon" is not a proverb expressing some sort of general "truth", like "La fortune sourit aux audacieux".In the Dutch proverb, the fortune is not a necessity. You use this proverb when you accidentally get some luck out of a misfortune.
The French proverb claims that there is always something good that comes out of something bad, no mather how bad it is.
How would this be translated into English?For me it's important that without the little bit of luck, the misfortune would have been even larger. For example: The waiter spilled coffee on my lap, but luckally it wasn't that hot (while I normally expect the coffe to be hot)
But maybe that's not the only possible use, it's how I most commonly use it.
Je pensais sinon à quelque chose comme "dans son malheur, il/elle a eu de la chance" ?I don't see anything better than the quite literal translation "Une chance dans le malheur a été que..." It is not very idiomatic but why not?