One thing you need to realize is that Trump is very blatant when he's trying to buy someone's loyalty.
He offered Cindy McCain some position in the State Department because he thought it would keep McCain from shytting on him from the Senate.
He gave Gingrich's wife some position with the Vatican so that Gingrich would be on Fox News 24/7 defending Trump.
He put Sanders in that position for basically the same reason. Huckabee still has a following in the evangelical community. It's some pure nepotism shyt. Standard operating procedure for Trump.