My son, Mark went to Oklahoma State University last year. Now he's back home in California for the summer. He had a friend of his who owns a horse trailer drive back his belongings. One of these was his bicycle which was lashed on top of the trailer, but below some other items. The trailer was also ferrying horses. Somehow, the bike was dislodged and ended up getting smashed beyond repair. My wife and I said that the friend should cover at least half the price of the bike. They gave him a bike that is probably worth maybe $150.00. His bike was almost brand new and he paid $1000.00 Who is liable in a case like this?