public class AccountTriggerHelper {
    public static void validateDeceasedAccounts(List<Account> newAccounts, Map<Id, Account> oldMap) {
        Set<Id> accIdSet = new Set<Id>();
        Map<Id, Case> casesMap = new Map<Id, Case>();

        for (Account acc : newAccounts) {
            Account oldAcc = oldMap.get(acc.Id);

            if (acc.Status__c == 'Deceased' && (
                    acc.DOB__c != oldAcc.DOB__c ||
                    acc.DOD__c != oldAcc.DOD__c ||
                    acc.Status__c != oldAcc.Status__c
                )) {
                if (acc.DOB__c == null || acc.DOD__c == null || acc.DOD__c <= acc.DOB__c) {
                    acc.addError('Please ensure that Date of Birth is populated, Date of Death is greater than Date of Birth, and Status is set to Deceased.');
                } else {
                    accIdSet.add(acc.Id);
                }
            }
        }

        if (!accIdSet.isEmpty()) {
            for (Case c : [SELECT Id, AccountId FROM Case WHERE AccountId IN :accIdSet AND Status != 'Closed']) {
                casesMap.put(c.AccountId, c);
            }
        }

        for (Account acc : newAccounts) {
            if (acc.Status__c == 'Deceased' && casesMap.containsKey(acc.Id)) {
                acc.addError('Please close all related cases before marking the status as Deceased.');
            }
        }
    }
}