No political experience what so ever, has never ran for political office either hasn't even run anything like an like an office or business or organization he would be a disaster as a candidate and a politician. Whoever is pushing this is not thinking this through at all.
Carson is an Evangelical Christian with a following. The Evangelical Right has no real candidate in the fray right now. If Huckabee doesn't enter the fray, then Carson carries the banner for those folks.
I suspect that Carson's candidacy is more for electing delegates and influencing the outcome of the ongoing GOP Civil War. The GOP needs to expand the map to take it to the next level, but are stalemated because of what their candidates need to do to win the GOP Presidential nomination. Many GOP regulars would love to have the religious conservatives go away, but (A) they have nowhere else to go, and (B) the GOP needs them more then they want to admit. Carson's "candidacy" is there to keep religious conservatives in the game, and to keep the GOP establishment in recognizing that they need the Evangelicals as part of their base.