I am convinced that Aokiji is pulling the Severus Snape with this latest chapter.
He is trying so hard to gain the trust of Teach by spilling Marine secrets like SWORD, which by the way even make Aokiji look like a traitor of the Blackbeard Pirates, and now fighting his former teacher Garp in front of Shiryu and Co. Knowing him, I see no clear motive as why he should be considered a real 10th Titantic Captain and a bad guy, when all he ever did were “good” deeds, saving Saul, Smoker or Robin (multiple times). It would be so out of character for him to swap teams and become a villain. After Akainu took the reigns, Aokiji said he didn’t want to work with the Marines while Akainu was on top, so he maybe came to Garp looking for options, how to still be of help and this was the best outcome.
When Garp yelled “and never forget, you are ALL the future of the Marines!!” I think he included his former prodigé Aokiji, and Aokiji knows it but he has to play along. Also maybe farfetched but when he froze Garp’s wound to stop the bleeding, for me it looks like he also froze his tears.