Depending upon the circumstances of the crime that a person if facing, reasonable force can be used to defend one from the danger. In the situation that you are writing about if you caught your daughter's former boyfriend peering in through the windows where there is a restraining order against him, the mere pulling of a firearm without discharging it does not seem to be a crime by you under the circumstances that you are writing about.I suggest that you make a police report about the situation you are writing about.