Patrick Francis Sheehan's priestly studies were in the Gregorian University in Rome.
He was posted to the Adamawa Mission assigned to the Irish Province of the Order of St Augustine by the Holy See.
In his time as a priest of Yola, Bishop Sheehan established the Third Order of St Augustine in the diocese under the authority of the Prior General in Rome.
On July 5, 1996, Bishop Sheehan was then transferred to Kano which was then an Apostolic Vicariate, i.e. not yet a diocese.
Bishop Patrick Francis Sheehan was found dead in his room in the Augustinian Priory of John's Lane, Dublin, on November 8, 2012.