I would tell him to stay the heck out of the game unless he knows what he's doing. Study for 2-3 years to get a good grip on the subject. I'm reading a book right now called The Power of Gold by Peter L. Bernstein. Even after everything I know about the subject, it's a great insight into monetary instruments. The book was published in 2000, so I'd be interested to know his take on the subject now. It covers ancient times until the year 2000.
As to your friend, knowledge is power. If I had heard that toy collecting was the in-thing to making money these days I wouldn't go out with $20K in my pocket buying up every toy I laid my eyes on. You have to know what you're doing and make up your mind as to the reason behind such a move. My advice to your friend is to stay out for 2-3 years and just watch daily what the "price" is doing and link it to current events. Try to figure out what's driving the moves instead of laying his children's bets before they're grown.