Answer:
It appears on the surface that Simon must give the stock to Fred and let Fred sell it, because Fred is in the higher tax bracket (i.e., 22% compared to Simons 12%). But for gift property, the basis of loss to the donee is the lower of (1) the adjusted basis of the donor, or (2) the amount of fair market value (FMV) on the date of the gift. Thus as Fred cannot take benefit of the loss, Simon must sell the stock, deduct the realized loss, and sales proceeds should be given to Fred.
When Simon sells the stock and handover the sale proceeds to Fred, in that case the capital gain received from the stock's sale will be taxed on Simon as per his tax bracket. The transfer of sale proceeds to Fred will not have any impact on tax.