Erik Fleming is asking a judge for mercy — admitting he helped supply ketamine in the lead-up to Matthew Perry‘s death … and saying he’ll spend the rest of his life trying to make up for it.

In new court documents, obtained by TMZ, Fleming is requesting just 3 months in prison, a 9-month residential drug treatment program, and 3 years of supervised release.

In a letter to the judge, he doesn’t sugarcoat his role, writing … “I knew it was illegal and wrong … I should never have agreed to acquire ketamine for Matt.”

This all comes after Jasveen Sangha — AKA the “Ketamine Queen” — was sentenced to 15 years earlier this month. Fleming is one of several people charged in connection to Perry’s death in October 2023 … when the 54-year-old actor was found unresponsive in a jacuzzi at his L.A.-area home. The medical examiner later ruled he died from the acute effects of ketamine.

Prosecutors say Fleming acted as a middleman … sourcing and delivering dozens of vials of ketamine to Perry’s live-in assistant, who then administered the drug.

But the feds say Fleming deserves far more than a slap on the wrist. They’re asking for 30 months in prison, plus 3 years’ supervised release … arguing he wasn’t just a desperate guy making a bad decision — he was a trained addiction counselor who repeatedly brokered drug deals for profit.

According to prosecutors … Fleming would’ve kept selling ketamine if Perry hadn’t died — pointing to evidence he was trying to line up another bulk order just days after delivering 25 vials.

Fleming’s team pushes back … saying he wasn’t acting as a medical professional and shouldn’t be treated like one who violated an oath.

TMZ also obtained letters from his family — including his father, who says Fleming is “deeply remorseful,” and his half-brother, who points to a relapse tied to family trauma, but says he’s now back on the path to sobriety.