I'm so very sorry. =(
It sounds like he lived a very long, very wonderful life in which he was loved constantly! I don't believe a rabbit could honestly ask for more.
I didn't even know rabbits could live to that age, but it was just his time, and I'm glad he is not in pain anymore.
((((hugs))))
It must be so hard to loose a pet thats been there with you so long.
RIP Wee One.