Depends if it's actually a funny joke.
A fixated mind might take an opportunity to blurt something out in a conversation.. It would be awkward, not really fit in with what's happening, and then the hiding reflex takes over. It gets played off as a joke to cover up what happened.
A active mind will dance and play with all kinds of ideas and sometimes will play with the concept of death, what it means and how bizarre the concept is on a lot of levels. Jokes will be throwaway comments that are at least mildly witty.