The NFL has no idea. The reason for that is while they could be told he is going to be, a judge could toss it out for some reason. Just like they could think he won't be and the DA goes forward.
As far as a trade, I would think that it would be "buyer be ware". Meaning, if the NFL allows a trade, the team receiving has to suffer if he is charged and/or put in jail. In short, once the Texans no longer have him it is not their responsibility anymore. Be it Philly, Miami or whoever. They are then 100% the one who has to deal with any fallout. Only seems fair seeing everyone knows the situation. It might be different if they were unaware.