My Husband's TMJ Has Been Very Sore, Just On One

My husband's TMJ has been very sore, just on one side. He has been wearing a night guard. He has also has some other areas of stiffness: knee, thumb, back. Now, he has a very mild tremor in his hands and he says he feels shake internally. He looked up symptoms and now thinks he has parkinson's disease. He is 52 and has always been very, very healthy. He is great physical shape other than one of his knees which he has pretty much wore out from running. FYI, there is a familiar tremor in his immediate family: dad, one of his brothers and his sister all shake. His dad did have parkinson's in addition.