There are a lot of medications that have been suggested to place on plants to preserve them and help it grow. Some have even placed sodium hypochlorite (bleach) for plant preservation. Unfortunately, there has been no data to show that these medications has successfully cured the tree of its ailment. Your best course of action is to consult a botanist or your neighborhood arborist or tree doctor. You can also check out this article on how to take care of your tree. [url=http://www.treesaregood.com/treecare/mature_care.aspx]Trees Are Good - Tree Care Information[/url]
Although just a tree, I would hate to see it die and go to waste.

Hope this helps.