Why should he endorse Fred?
Why not?
1) Fred's standing in the polls has been consistently higher than Hunters;
2) An endorsement of Hunter would add nothing statistically poll-wise to Hunter's campaign;
3) Tancredo's buddy, Steve King has endorsed Fred; was that the first act?
4) Fred's standing on immigration, Tancredo's single hot-button issue, has been consistently conservative.
I see no reason not to.