I think TQ has a really good idea about contacting the local HD shop and locals riders in the area. The more eyeballs on the watch, the better your chances.
I'd also post a pic of him on the local telephone poles, Walmart, etc. And I'd say truck was stolen. You can keep the truck just bring my little buddy back. No questions asked (for now).
Hang in there brother - we're all praying for ya.