B: Mommy makes the best smoothies. She's the one in this family who knows the most because she's the oldest.
Me: mm hmm (nodding, wholeheartedly in agreement)
B: Yeah,...she's the oldest. And she's a doctor, so she knows how to make the best smoothies. She's probly gonna be the one who dies first out of all of us.
Me: (Trying to keep a straight face and at the same time feeling concerned, preparing for follow up questions). Really Ben?, What makes you say that?
B: well she's the oldest so she will be the first one to get to a hundred. That's really old!!
(I told him none of us knows when we're gonna die and that's why we should live every day as happy as we can. But I guess he knows we won't be around forever.)