I'm trying to feel sympathy for 'ya bud, but how in Gods green earth could you wait 8 years!??? Honestly, friend of the family or not, you kind of put yourself ina tight spot by sitting on this one so long.
In any case,I'd take a couple buddies with me and walk in unannounced and tell him you are there to pick up your hide and a full refund plus interest. I'd settle for nothing less. No way in hell could that hide still be at the tannery. If he stalls, stammers or otherwise can't produce, you'll have to be the judge of what happens immediately after. I know what I'd do.