Hey, we're all born and we all die.
Being able to laugh about this kind of humor (jokes about death) is good for you (as long as it actually is funny). It can help you deal with cancer as a terrifying disease (as long as you don't have any stuper-stitions). Laughing about Cancer is not scary. Telling jokes about death in genral should be encouraged. Much like the Kids In The Hall's Cancer Boy, there is an archetype for all kinds of people.
After all, we all have at least 2 things in common and shying away from the inevitable isn't going to make it less real no matter what you belive.