This is really something very responsible to think about. Do you have a life insurance policy? If not, I suggest that you obtain one. My husband and I have been going 'round and 'round about this, as I ask him, "What if you die; I die? What's the plan?" We are in the process right now of wrapping up a policy. We took our blood tests and medical exams. I got my results, but we haven't gotten his. But, the ball is rolling. It just a responsible decision to make as a parent.
With that, keep in mind that while kids do have great imaginations, they do understand the tangible. "Who will -love- me?" is not a real tangible thing, but the motive behind the question might really be. He might have things like the school, house, family, friends on his mind. Like, will all of those things stay the same if you die? And I think that reinforcing those real live tangible things can bring a lot of security to him over this.
At 6.5 years old, it would be perfectly fine to tell him that you've made a plan... that somethings would change. Like perhaps, he might have to move to Grandma and Grandpa's house. But, he could still bring his basket ball there. I encourage you to give him a name, a face, and tangible things to hold onto for security. And above and beyond it all... give him a relationship. Really, that's the best insurance you could ever possibly purchase. And the currency is your time making that relationship real to him, intimate, and trusted.
--OK, the preaching begins here--
This is nothing new, according to Christian tradition, we dedicate or baptize our babies and pick out God parents who are "traditionally" supposed to reinforce biblical pricipals into the child's life. In picking the God parents, they should be spiritually mature and committed to "parenting" the family in God's ways. The relationship is built over time, reinforced, and familiar to the children. If the biological parent dies, they are the ones that are there for the child to turn to with questions like "Where is Mommy?" or "What happens when we die?". You can certainly give answers now, but in crisis reinforcement is going to be vital to your little one's mental, spiritual, and emotional health. After all, how many times do we wonder about these things and ask questions.
So, my overall encouragment for you is to put the passion behind those sweet tender hearted tears into action. Get some life insurance: the kind you purchase with your money and the kind you purchase with your time.
And, most importantly pray with your little guy. Pray with him, and let him know that you are telling God who's going to be in charge of taking care of him in all the important ways here on earth. And then, pray for them also together. That God will ready their hearts, open opportunity for you all to spend more time together now even when nothing like dying has happened, and that God would take care of them, so that they can take care of him.
Just think about it... that's what your little guy needs anyways. He needs whoever is taking care of him to be taken care of by God. Do you have that in your life? Does he know that God takes care of you so that you can provide for him, make a way for him, give him the best, and just be a happy, peaceful, person. It's important for him to know that if you die, none of that will stop because God is the same, yesterday, today, and forever.
God is good! ~~~ all the time.