Taking Charge — Francine Pascal

MAKING CHANGES...
Even though Jessica and Elizabeth don't always see eye to eye, they know their problems aren't half as bad as those of their classmate, Patrick Morris. At least the twins have one big, happy family.

Patricks's parents seem to be the meanest people in the world. They don't let him have more than one friend visit at a time, they refuse to let him go to the big rock concert with the gang, and worst of all, they forbid him to join the Sweet Valley band!

That's when Patrick decides to take matters into his own hands. And if his parents don't listen this time, they'll really be sorry!