Unsure
Christian was not at all thrilled about his brother's decision. If he had even remotely mentioned that he knew the pureblooded Alpha who was once the prime suspect of the witch mayhem personally he would have done everything in his power to keep them apart. He knew his brother was strong enough to fend off usual alphas, but even Christian himself wasn't sure how he would tackle a pureblood, let alone be okay with Caleb choosing one as a mate.
He knew his brother was smart, and made smart decisions which is why he never interefered with his personal affaits, which is why he failed to understand why on earth would his baby brother make such a dumb decision.
Christian brought up all the times they had got the scent of Ashton, and pointed out to Caleb how shady those incidences were. Caleb however tried to defend Ashton and presented him with a valid argument for each and every encounter, as if he had way too much faith in Ashton.