Tremors are a frequent side effect of medications. And yes, I believe poor ol' Ozzy has burned out a few neurons from his years of drug and alcohol abuse.
But as profane as the Osbournes are, I DO think they are doing a lot of good things as a family. The parents are actively involved with their children. They CARE about where they go, who they see, what they do. They talk to each other (well, maybe YELL at each other is more like it), and they really seem to care about each other.
Which is a lot more than many families I see nowadays doing.