My first ever tab here so might not be perfect but I've noticed no one else has had an attempt at this so here's how I play it. Capo on first threat, play with alternating base (bottom two strings like most Johnny Cash songs) Also when playing C alternate between having your ring finger 3rd threat from the A string to low E string. This is what Johnny was doing so watch his video if you don't understand.

^CWell Uncle Bill was my Mothers Brother, ^Ftall lanky ma^Cn ^CBut somewhere back in Uncle Bill's life, he took to sniffing cocaine. ^CI'd find him out in the back yard, ^Fsitting against a tree^C. ^CHis eyes bugged out in a cocaine stare, ^Fand his mind in a cocaine drea^Cm. ^CWell one fall day when Uncle Bill was ^Fhaving a cocaine fit^C, ^CHe said Louise this ^Gcoke's no good ^Fand I've made up my mind to qui^Ct. ^CNow you take this key and I'l^Gl go upstairs and ^Fthen you lock the doo^Cr, ^Cand Lord I swear I ^Gwont come down, ^Ftill I don't want dope no more^C.

Chorus

^CWell he stomped the floor and he ^Gbeat the door and he m^Foaned a mournful cr^Cy. ^CWhen the last cocaine went ^Gthrough his brain we ^Fthought he'd surely ^Cdie. ^CHe yelled and he cussed and he fe^Gll on the floor and we ^Falmost gave up hop^Ce ^CAs long as I live I ^Gwont forget when ^FUncle Bill quit dope^C.

^CWell for the first few hours we heard not a sound, ^Fupstairs was quiet and stil^Cl. ^Cand then all of a sudden we heard a shriek of ^Fpain from Uncle Bil^Cl. ^CHe bounced out of bed and across the room, ^FI heard him break a chai^Cr. ^CAnd then another scream louder than the first as he ^Fripped out a hunk of his hai^Cr. ^CMy Mother kissed us all that night, ^Fas brother and I lay in be^Cd. ^CWe wondered if poor old Uncle Bill was ^Fdieing or already dea^Cd. ^CBut all night long we listened to him as he ^Fraved pleaded and calle^Cd. ^Cand I swear I heard his finger nails tearing the ^Fpaper off the wall^Cs.

Chorus

^CAfter fourteen days and nights of hell, it ^Fgrew quiet over hea^Cd. ^CAnd I peered past mother, as she unlocked the door ^Fexpecting to find him dea^Cd. ^CBut to my surprise there was Uncle Bill, as ^Fshiny as a brand new d^Collar. ^CHis hair was combed and his beard was gone, ^Fhe'd grown two inches talle^Cr. ^CIn his old blue suite and his patterned shoes, he was ^Fquite a sight to se^Ce. ^CThe light was back in his deep blue eyes, he ^Fturned to mother and m^Ce. ^CHe said Louise I've been through hell and I ^Fnearly went insan^Ce. ^CBut I finally beat the devils habit, I ^Fbeat the demon cocain^Ce.

Chorus

^CWell he stomped the floor and he ^Gbeat the door and he m^Foaned a mournful cr^Cy. ^CWhen the last cocaine went ^Gthrough his brain we ^Fthought he'd surely ^Cdie. ^CHe screamed and he hollered and h^Ge fell on the floor and^F we almost gave up^C hope ^CAs long as I live I ^Gwont forget when ^FUncle Bill quit dope^C.

Johnny Cash - When uncle bill quit dope