Can Old People Fight Depression?

It is really possible for elderly people to fight depression? This article provides a few natural remedies that are believed to cure elderly people from depression. It states that group activities, therapy, and exercise are "group-based physical exercise programs...[which] can reduce depression in older adults." But could something this basic really help? I would think curing depression takes a lot more than just regular exercise and activities. While skimming the book, "The Treatment of Emotional Disorders," I found a report suggesting that family therapy is the most sufficient. If this is the case, why won't families take the initiative to prevent this disorder. Why do they make such an effortful attempt to save their depressed patient when it is already too late?