If you dream of an old man that you know then you want to pay attention to what he is doing in the dream.
His actions are the area in which you need assistance in your waking life.
If this old man, for instance, is sitting in a chair and enjoying coffee while reading a paper this is a dream to take things more slowly in your waking life and to see wisdom from those around you.
There is likely an older man in your waking life such as a father, uncle, or boss that can lead you in the right direction or out of trouble in your waking life.
When an old man is asking you for help, this is a sign that you need to be more careful in your own life about whom you trust or that you cannot trust your own instincts.
The old man is also representative to paying more attention to your environment, your work, and health in the waking world.
To dream that you are old or older than you are a warning about these areas.
Examine these areas in your life where you are not paying enough attention to.