Give Bert an opportunity to talk out all of his thought about the piano.
Wait until he has told all, and you have planned a substitute for
piano-wrecking before informing him of the gravity of his misconduct.
Possibly that item can be passed over lightly.
Get answers to these questions: “Are you particularly interested in
pianos or do you take an interest in all kinds of mechanisms? What are
you planning to do for a living? What would you do if I found you a
place in a piano store, or in a machine shop, for spare time work? Would
you stiffen up your studies? Would your parents be willing for me to
make an arrangement of this sort? How will you pay for having a piano
man go over our instrument and see that everything is in order?”