Complex sentence: The Hecks aren't able to help, forcing Cindy's family to move in with her grandparents and seemingly ending her relationship with Brick, until it is shown that her grandparents live only a block away.
Split into simpler sentences: The Hecks aren't able to help, forcing Cindy's family to move in with her grandparents. This seemingly ends her relationship with Brick, until it is shown that her grandparents live only a block away.