Is there an "investigative reporter" at one of the local television stations? The public spotlight might make Wal-Mart management a little more receptive to you parent's situation.
Just a thought. Hope your parents get some justice here.
I agree, get the local paper or tv station involved. Make a public stink. Contact the elected official in charge of the police department and complain. Complain to regional Wal-Mart managers.
E-mail/fax O'Reilly, Ann Landers, etc. Any national consumer affairs organization. Complain to senior services, file an ADA complaint, complain to AARP.
The more places you complain and provide them with the local Wal-mart manager's name and phone number, the more enquiries will be made and the bigger problem you become, the faster they will fix it to shut you up.