Legal Question in Criminal Law in Tennessee

Possession for his/her own use? In Tennessee, that's a misdemeanor. Unless it's a third offense, that's 11 months 29 days in the local jail at worst.

Possession with intent to sell or deliver is a Class B felony, and as a Schedule I drug, your defendant is looking at 8-12 years to serve in the penitentiary. Eligible for parole after 30%.

That's for a first time offender. If your character has a record, it can go even higher, but there are other factors that could affect the sentence and parole eligibility, depending on the dramatic effect sought. Chat up a Public Defender in your jurisdiction.