codeine1337 said:
If you mean spiritually, the full name is not really needed.
With the date of birth if you also know the place of birth then you can trace his birth chart and use it to understand when he is going through a hard time in life and then attack him with appropriate work.
By having his birth chart and giving it a correct interpretation, you will get to know him better than anyone else, better than himself.
You have to know what you are doing, and you have to make wise choices in this, otherwise you better leave him in his misery (I suppose).
I have one last off-topic thought, for some reason I think it's some street crap, your user and profile picture suggest this. Just a thought, nothing personal.