I would only list related work experience, althought if he has none (or one position) that will make for a thin resume.
I'd only list certifications that are significant. Example: list the state certification as a police officer. i would not list stuff like OC spray, baton, firearms qual, etc.; though again that makes for a thin resume. I would not include copies.
Martial arts experience, if properly worded and inserted in the correct area, could be beneficial.
He understands very few places will accept only a resume, right? In LE, it is basically an addendum to the application.
"No amount of indoctrination or textbook learning will in themselves develop more than efficient mediocrity. Operations should be handled with a combination of force, subtlety, shrewdness, guile, and knowledge born of actual experience." - DF