In plaintiffs' suit against their father, their half-sisters, and their half-sisters' mother for elder abuse and other related causes of action that had belonged to their grandmother when she died, trial court's grant of defendants' motion for summary judgment for lack of standing is affirmed where: 1) plaintiffs were former beneficiaries of their grandmother's trust, as they already had been paid the amounts they were owed under the trust, and as such, plaintiffs were not "interested persons" for purposes of pursuing this elder abuse action under Welfare and Institutions Code section 1567.3(d); 2) the trial court was correct in concluding that the only way plaintiffs would have standing to pursue this action was if they succeeded to their grandmother's causes of action because their father and their half-sisters all were deemed to have predeceased the grandmother under Probate Code section 259; 3) there was no triable issue of fact as to whether one of the half-sisters acted in bad faith or engaged in reckless, malicious, oppressive, or fraudulent conduct, she cannot be deemed to have predeceased the grandmother under Probate Code section 259; and 4) even if the trial court erred in denying plaintiffs' motion to compel the half-sister to answer certain deposition questions, plaintiffs have failed to show any prejudice from that error because they failed to show it is reasonably probable they could have avoided summary judgment if the trial court had compelled the half-sister to answer.