Marty and Janet's family ties are not explained.
At the end of "I'm With Stupid", Marty and Janet remember they don't even have a son. In fact, since some couples never have children, it's never revealed if they even have any kids at all, or if they're even related to Patrick. "Procrastination" was never MEANT to be cut.
The episode in future airings looks more grainy and too much of it was cut to justify any one thing being the main culprit. Any excuse given for why it was cut in the first place has been just speculation, with no official confirmation one way or the other. Contrast with "Just One Bite", where the offending scene is removed in a way that seems to imply more context but with extra footage and editing rather than an abrupt smash cut as in this scene. It is possible the file for airing the episode became corrupted at some point. Since the uncut version was the one on DVD and now airs on both streaming and Nicktoons, this seems plausible.