No such thing as a FEDERAL CCW. Law enforcement officers (Fed, State and local) can carry. RETIRED LEOs that meet the requirements (requalifying with weapon, etc) can carry. As noted earlier, that IS provided for in Federal law. It does not extend to family members, neighbors, good friends, or next of kin.
Not that you asked me for it, but would put as much distance between him and you as you can. A couple of zip codes worth of distance. He will manage to self destruct in a spectacular fashion. You want to be outside the blast radius when that happens.