John Thomas Has Decided He Wants To Marry...

Recently John Thomas has become quite interested in old people and dying. I am guessing someone in his class has lost a loved one and they've talked. He's asked me a lot about his Nanny that passed 2 years ago and what she's doing in Heaven. Well the other day on the ride home, he starts questioning me about his Granny (John's Great Grandmother).
John Thomas: Mommy, is Granny old.
Me: Yes John Thomas she is 90, and will be 91 in a couple of weeks.
John Thomas: Is that why she has all those spots?
Me: Yes.
John Thomas: You have spots, are you old.
Me: No John Thomas, Mommy has freckles.
John Thomas: Is Granny going to die, like Nanny?
Me: Granny is very healthy.
John Thomas: I want to marry Granny.
Me: Why do you want to marry Granny?
John Thomas: Cause I love her and if I marry her, she won't die.
Me: Okay (I mean what else can you say to that).