I don't know about DC but one way to approach this would be to try and get employment with a private school. Some of them don't require certification. I have a friend who works at a very prestigious private school with only a BFA in photo and no prior teaching experience. Of course, he is exremely fun-loving and one of the most charismatic people I know, so that helps. Some private schools will pay or help pay for continuing education. He might also consider volunteering to assist with children's programs offered by a museum. This could give him some good experience. I am currently doing this myself as I simultaneously work on my art ed masters ( I have a BS in photo)My program at CWRU seems to be geared towards practicing artists/BFAs who want to become teachers. Its a one year program which is very intensive (although I am doing it partime while working fulltime at my current job). But the one year cuts down on the tuition which is very high at CWRU which is a private sc
hool. I think its a great program and it seems to be very well respected in this area. I do know a 3rd grade classroom teacher who got her masters through a video degree program. But I'm actually disgusted that her school district accepted that.
P.S. As a man, your son also has an advantage getting a job in a female dominated field.
P.P.S He might also consider volunteering as an aide in an art classroom. I don't know anyone who has done this in art but I volunteered for awhile in a kindergarten classroom at my old elementary school. The teacher was amazing and I learned a lot but still don't know how she managed to do what she did. Probablly one of the best experiences I've had to prepare me as a teacher. Found out about her from classmates (while I was still in elementary) who were raving about her and begging to be cross-age helpers. But I digress.... Good luck to you and your son!