The FDMI is a cool gig, you can't get that in Bernalillo county...but every other county in NM has one or more FDMI. They look for Paramedics or anyone that has dead body experience. They also have a 2 day training seminar every year in March that's open to the public. I think it's about 300 bucks, it doesn't get you certified but it would help the resume. If he can get certified as a Medico-legal Death Investigator he's probably a shoe in. Getting on in Bernalillo County is virtually impossible unless you have a cert and a paramedic licence or something. They will take students as paid interns in the OMI as morphology techs...this is also a sure way to get into the business. It's a pretty thankless gory job though, but perfect to learn your way in and build some relationships.
I only know all of this because I was trying to get on for years. If I lived outside of Bernalillo county I would be an FDMI...but you have to live in the county you work, and FDMIs are only rural (outside of Bernalillo county). Good luck to him.