Three of his seven children became harpsichord makers: Angela van den Brant was married to Joannes Couchet and following his death, she worked with Simon Hagaerts to maintain her late husband's workshop and train her sons.
[1] Petrus Joannes Couchet became a master harpsichord maker and member of the Guild of St Luke in 1655 or 1656; Joseph Joannes Couchet became a member in 1666 or 1667.
His instruments in existence today are a single manual harpsichord dated 1671 (possibly by Petrus Joannes), given a ravalement and made into a double manual by Pascal Taskin in 1778; a single manual harpsichord dated 1679; and a double manual harpsichord dated 1680 and again given a grand ravalement by Taskin in 1781; a similar unsigned instrument likewise worked on by Taskin may also have been his.
Maria Abraham Couchet likewise became a member of the guild in 1666 or 1667.
The Couchet family went on to make further innovations to the models established by Ruckers, building a double manual harpsichord with extended range of FF to d''', and sometimes introducing registrations of 8' 8' or 8' 8' 4' instead of the then-usual 8' 4'.