Yes he needs a lawyer. To charge someone with possesion of drugs, it not necessarily that the the drugs be actually in a person's physical possession. Someone can be charged and even convicted of drug possession if they are found to be in "constructive" possession which essentially means the drugs were in their custody and control though not necessarily physically on their person.
Also, since the amount recovered is in excess of an ounce, your son may be facing felony possession charges (possession with intent to distribute). Your son's co-defendant may claim your son knew about the drugs or the drugs were his so it is imperative that he retain his own attorney.
If he is over 18 and cannot afford an attorney, he can apply for a public defender. If he is under 18 and you cannot afford to hire him an attorney, then you can apply for a public defender on his behalf.
I wish you the best of luck and don't hesitate to ask further questions as needed. Please remember to click "ACCEPT" and any feedback is appreciated:)
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