He's okay.
You're not okay, you're not going to be okay. Your spouse and your other kids, they're not going to be okay, not for a while. You'll never be the same. It'll never be the same. My wife lost her brother a decade ago, and there are still times she cries about it. It's still a dark spot in the family. It's okay to NOT be okay for as long as you need.
But you can know, with certainty, that he's okay. Heck, from here on out, he's got the best gameday seats in the house.