If he has only just been arrested and is still in the local county jail, he will come before the court
for his arraignement. That's where the charges will be read in court and he will be asked how he pleads. The only answer to this at an arraignment is not guilty, because that is the one which will keep all of his rights open until he can get advised by counsel. It is also where, if he cannot afford a private lawyer and no pubic defender has already been assigned to him, he can ask the judge for a public defender, as this is where his Constitutional right to counsel first attaches.
Generally, both the prosecution and the defense also get heard here as to bail status. In general, the DA willl argue why bail should be set and set high. The defense will make a counter argument for the defendant's release on his own recognizance. To determine bail, the judge looks at the prior criminal
history and background of the defendant, the seriousness and strength of the state's case, and whether the defendant has any ties to the community. Generally thereafter, a new date is set for the case to start going forward.
The seriousness of the case depends upon the type of drug the defendant had in his possession and the amount of it. In most cases, unless the amount is miniscule, possession would likely be a felony charge. However, with a straight possession case (no intent to sell) if he did not want to fight the case, and if he has no prior contact with the law, he is looking usually at nothing worse than probation. And if this was for his personal use and it is believed that he has a substance dependency, there are even help-oriented programs, such as Drug Court, that would allow a defendant to work off his conviction by complying with supervision and treatment and come out without a criminal record