He'll show up. Typically if they get tired of waiting they will wander back to their static starting spot. It may take him a few "game days" to get there though.
You could get his PRID code and have him MoveTo Player. That should pull him up.
I had this happen with Moll the Lioness. I had somehow clicked "time to split ways" without realizing it. She was eating in the Bee & Barb back in Riften a short time later. Still had all my gear.