I did know Mighty. I adopted him to you those many years ago. I'm sorry that we've been out of touch with each other. I'm even more sorry to hear that you've lost your very special boy. He was an incredibly sweet boy and I know your heart must be really hurting. If you ever need/want to talk, email me at firstname.lastname@example.org (different than the one I used to have).
Losing your best friend is never easy but please know that he loved you and never felt like you let him down. When I lost Crooke, I kept thinking, if only I'd done something different but I know now that it just doesn't work that way. When it's time to go, it's time. It doesn't make it hurt any less, though. Time will help you to heal. In the meantime, Greytalk can be a greyt place to help the grieving process because so many of us understand what you are experiencing. It sometimes helps to be around others with similar experiences.
Here is a link to a couple of pics from when he was a foster
Hugs and take care,