Gave someone his prescription medicine?:
If he doesn't already have a competent attorney, you need to hire one immediately.

These types of cases can be especially complicated, as there is more at stake than you may realize.  For instance, a conviction on a drug charge may mean reduce or little eligibility for federal student aid in college, (if he decides to go that route).  Although it IS against the law to give anyone a drug that is not prescribed for  him, there is always grounds to review this with the prosecuting authority.

I  urge you to contact a skilled criminal defense attorney in your area.  Be prepared to pay a sizeable retainer.  For a referral to a criminal defense attorney, contact your local or state bar association.