Incidentally, if you have any records that are valuable do NOT play them! Those old music centres were great for trashing vinyl/shellac at the best of times, and if it's not set up properly it can do a lot of damage, and if you're using an old stylus chances are they'll be ruined very quickly. You're unlikely to have anything worth $$$ but be careful! Basically if it's Blues don't play it without checking up on it, and some jazz is sought after too. Anything with Robert Johnson written on it keep safe. 
oh come on... in my opinion it's more important his dad got this blast-of-the-past experience then any money can provide. How many kids would do such a nice thing :-)
Tom UK
