"Seen Him" and "Saw Him"

"Saw him," I heard my roommate mumbling something when he was watching TV news.
"Why? Did she say 'seen him'?"
"Yes, she said 'The last time I seen him'"


Right now, CNN is doing a breaking news report on the Mall shooting in Kansas City, Missouri, and one woman was interviewed off camera. The reporter asked her why she fled to a nearby store but not stayed in her car. She replied she "seen" the shooter when she was in the car (so she fled to the store right then perhaps ... I don't remember the details).

My roommate is, well, how should I put it, quite sensitive about how people talk. Just a few minutes ago, he corrected another interviewee's English--the person said "Me and my girlfriend", and my roommate said "My girlfriend and I".