At the beginning of the episode, whose yard sale were Ken and Nick at? And how did Nick's dad sell his son's drums without Nick knowing about it?
https://www.change.org/p/nickelodeon-viacom-keep-sex-fetishism-out-of-children-s-television
They were just at a yard sale--it had no connection to anyone in the series and we did not see that house again during the show's run.
I would guess that the dad waited until Nick went to school and then packed those babies up. I always wondered if he really sold them or was just storing them somewhere to send the message that Nick needed to get his act together.
That idea would explain why after Nick demanded the money his dad made from selling his drumset, he hesitated for awhile and then finally refused.
https://www.change.org/p/nickelodeon-viacom-keep-sex-fetishism-out-of-children-s-television