It is always a little awkward when a contestant on a light-hearted programme suffers a bereavement and has to leave. I thought Ant and Dec handled it well, being sober and respectful when they discussed it, then letting the topic go. I am sure the others have discussed him a lot: he was a huge part of Nadia's experience, and she will have wanted to tell the others everything that went on before they were together. But IAC almost never broadcasts what you might call 'normal conversations': the bread and butter conversations about friends and family that must fill most of their waking hours.
I assume that rtv shows have a protocol for what they would do if a contestant was badly injured; Big Brother had a housemate break her leg, but her injury was not terribly severe. Presumably if she had broken her back, say, they might have called the whole thing off, as BB Serbia did when (this is a horrible thing) three evictees were killed in a car crash.