Well unless it was suicide I don't see the purpose of reading the journals...and even then I'd say he probably locked it for a specific reason...otherwise he would have left a blatent note or something along those lines.
I say bury the laptop with him. He kept his stuff secret in life, they might as well stay that way in death.
I'm sorry that your friend died, however, you need to stop posting these as no one will help you out in this situation. We can't give you advice on how to obtain information that others don't want you to see. This thread will also be closed.