The potential spouse needs to be told. It would be very wrong…like zulm…not to do so. It’s underhanded.
A friend of mine had told me once how her older sister had once gotten a rishta. And the guy’s parents were VERY persistent…about getting the marriage over and done with as soon as possible. (I’ve heard that it’s not unreasonable to be wary of rishtas where there is immense pressure on time). Anyhow…my friend’s family became very suspicious about why they wanted to rush things. It was then later found out, through investigation, that the guy was impotent. And this was not revealed at all to the girl’s family…although the guy’s family was well aware.