The show " The Ghost Whisperer"

Joel overheard his Aunt Ivy and Uncle Gulam talking about this show "The Ghost Whisperer". So he wanted to see what is the show about. After watching the first time, he asked me what it is about. I told him it is about people who has died and who wanted to do something before they went to heaven. Joel then told me " Mummy when i died i want to say good bye to you and every body." I was shocked to hear this. I said to him "hey, mummy is older so mummy must die earlier then you." You don't talk like that". I also tried telling him that he should actually live as if there is no tomorrow, that is, do your best every day so that when we die we won't have things that we still have not done. Well, my explaination was too vague, as i don't know how to put it to a 7 years old. About 1 or 2 weeks passed, Joel then asked "Mummy, anyone in our family died?" Do they also stayed and do what they want to do before they go heaven?" I was speechless, has no idea what to say so the usual "Joel, it is just a show, please don't keep thinking about it." Sigh, but i saw him looking behind his back as if to make sure noone is behind him once after bathing him!" Kinda of regret not finding out more about the show before i let him watch it.