Short version - Get him counsel. Do it now.
Sadly, it is not uncommon for someone's first thought to be bail, even when paying for bail doesn't lead to a release.
He needs counsel who can assist him, either the same retained counsel working with his problems in both counties, or counsel from each county communicating so each knows the status of the other case.
On the motion to accelerate, the deferred sentence, the reason for the acceleration, and the ability to address that problem, are both very important. However, the existence of the new charge can create an entirely new basis to accelerate the existing deferred.
Since bail has been posted, look to get him transferred to Oklahoma county. Once there, bail can be posted there. Just be aware, once you've posted bail, you've shown he has the ability to hire counsel.
It is ideal to get one attorney to handle both courts. Or if he cannot bail out of OK County, let him get a PD there and then hire an attorney for the other matter.
What the result will be will depend a lot on which Judge has the acceleration case. so it's hard to predict without that information as well as other factors. And you should only give those details to an attorney in a confidential setting rather than on here. Most defense attorneys will give a first free consultation for this very reason. I recommend calling a few.
This information is for general information purposes only and does not create an attorney-client relationship.