I'm pretty sure he was saying the snake is not responding to f/t, so it would doubtfully respond to anything else dead..
Many people feed live all the time to hundreds of snakes with no problems. If you see the mouse starting to bite the snake (which it probably won't be able to even if it looks like it is) you can stick a pen in it's mouth to make sure it doesn't do any damage.
Don't hover over the snake though, it could cause it to not feed.
Also, if you want to feed f/t at all, you should try feeding in the enclosure if you are already not. They will feel much safer in their own home then in a separate new place.