My friend has a fig tree that produces figs with dried up centers. This tree is an off shoot from my tree and is one of many that I have given to friends over the pass years. All the other trees are producing great figs.
I would definitely call the Ag extension office and get some advice on treatment. For your friend, I'd recommend disposing in the garbage all fallen leaves, particularly when it goes dormant. Check the local area for other trees that may be infected. There are dormant sprays for other fruit crops but I'm not sure it'll work or is licensed on Figs. See what the extension office suggests. Also take a look at this description: http://www.crfg.org/pubs/ff/fig.html and possibly contact the California Rare Fruit Growers for an ID/solution.