Turning 5 blues

Uh oh!!! I have a 4 almost 5 years that I think is panicking about getting older.  Noah will be 5 on Feb. 4th.  Week before last he told me he wanted to stay little forever.  He thought it would be a great idea if he stopped eating so he wouldn't grow anymore, I begged to differ.  Then last week he said he didn't want to turn 5 and start losing his teeth like Owen and Livi did.  Again he had a good idea.  He thought he should stop brushing his teeth so they won't fall out.  Again I begged to differ.  Both of these came at random times and not when I was having him brush his teeth or eat a meal.  They are true concerns for him.  Well tonite Nick and I spent a good 30 minute consoling this seriously crying almost 5 year old.  He was so upset over the thought of Nick and I plus himself getting old and being in a graveyard. He kept asking who was going to take care of him when we were gone.  He doesn't want us to get old.  We didn't want to lie to him and say we are never getting old, so I said you don't have to worry about this for a very long time.  He seemed ok with the answer and went to watch tv.  Then I hear him sobbing again.  I ask him what's wrong now, he says after a really long time and you get old and go to a graveyard who's going to take care of us.  It was so heart breaking :-(. I'm really hoping this passes soon and has nothing to do with the fact that he is going to be a big brother to a baby BOY!!!!!