In addition to bibliotherapy that might help not only children grieving the loss of a marriage, but also one of both parties, there are many movies that take a look at dysfunctional families, issues arising in divorce, how to handle divorce and custody issues, and more particularly, how NOT to handle them. Here's a helpful list of some of those movies, with a brief summary. You might send this on to someone it may benefit.
One movie not on the list is "The Squid and the Whale." The movie is not for the faint of heart, but sure provides a good illustration to parents on how they ought to proceed in a divorce or custody matter to avoid completely screwing up their children. This is available through Netflix and video stores.