It's also possible that he has no reason to be antagonistic because there's nothing he can do.

After all, the Orochimaru we have here doesn't have a real body, and it's only a tiny piece of Orochimaru's spirit.

It's entirely possible that, like the chakra that the 4th sealed for himself and Kushina inside of Naruto, that there's only so much he will be able to do before he exhausts that chakra and he disappears.

Draining his own chakra from Kabuto may have given him more time, but it could still be only a matter of time before he dies again. And if he knows that, he may consider his actions he takes to be less of a "how can I gain the upper hand" and more of a "what can I do to see my goals achieved by another now that they are beyond my reach."