Don't be hard with your son. A properly maintained flipping mechanism is supposed to take abuse, so it is likely that it was a matter of time before your flipper would fail with any use.

Is it not flipping at all or is it flipping weakly?

Also, have you exhausted the built-in diagnostics? (Switch tests and coil tests could at least confirm which parts are OK.)

There's something else wrong with the machine. No machine should require a rebuild after one year of home use. You can try a rebuild if you already bought the parts, but I wouldn't be surprised if it doesn't restore the flipper strength.

Have you checked the EOS switches on the flippers? You should be able to move the flipper bats by hand and see the EOS switches open/close in the switch diagnostic.