Because Zach and Coop don't go to the same schools we worried a bit about them not seeing enough of each other once they left the daycare, but we have kept in contact (made easier by the fact that Cooper's parents are great people and we love them too!) and they still LOVE to see each other.
My parents moved a lot when I was a kid - usually every two years until I got into the third grade. For that and other reasons too much to get into here, I didn't make close friends that easily so I never had a best friend like Zachary does. So I am in awe of this relationship they have. They remind me of a relationship that Paul has described between he and his best friend Tom - they met in the third grade and to this day are still good friends - Tom was the best man at our wedding.
I love watching Zachary and cooper together - there is no other friend that makes Zachary as happy as Cooper. He is so excited to see him and just grins ear-to-ear as long as they are together. it makes me feel good to see them together. They are both great boys. They are smart, polite, sweet - everything little boys should be. And maybe it sounds trite, but in a world where at the age of 5 or 6 kids are already talking about sex, violence, drugs, and other adult themes it's great to know that Zach has a best buddy who likes to talk about trains, their schools, burping (yes, bodily functions are still funny), cartoons, etc. makes me feel good. If the worst you have to reprimand your son for with his best buddy is too much "potty humor" then I think you have a good thing going.
Who knows what the future will bring, but I have hope that in another 30 years Zach and Coop will be exchanging emails (or whatever the communication vehicle is then) about their families and jobs like Paul and Tom do today. They laugh about things they did in the third grade and high school - when they were together almost every day and about the fun they had in college and beyond when they weren't together every day but that friendship remained strong. I envy both Zach and Paul. I'm just now finding some of those life-long friends - People like Cooper's mommy, Kim. I'm grateful for those friends that God has given me now, and I'm grateful that He has seen fit to send Zachary one this early. God is good. Thank him for your best friend - then hug her or him.