In Arizona, is a will valid if it was typed at home, no witnesses to the testators signature, never filed with the courts and no probate either

Simple answers are rare in the law, but I can give you some information that may help.  Wills only apply to probate property, which is property owned solely by someone who has died (the decedent) with no named beneficiary or pay-on-death designation.  These type of assets require some sort of probate process to transfer.  To transfer, you must be appointed personal representative of the estate, which is done by filing an application with the probate court for the region where the decedent lived.  If the decedent's probate assets are worth less than $75,000 and there is no real estate, you can use a small estate affidavit to transfer them rather than probate appointment.  You can be appointed personal representative of the decedent's estate without the Will.  On the court form, you could indicate that you have been unable to find the Will.  You also could incllude information on this person you believe has a Will.  Either way, you would get appointed as your parents' heirs.  You then would have the legal authority to pay estate bills and then distribute the remaining assets in accordance with either the Will (if the person comes forward and files it) or with the laws of intestacy.  The laws of intestacy provide that assets go to children if there is no surviving spouse.  If you have a deceased sibling who left children, those children are entitled to their parent's intestate share.  Again, the laws of intestacy only apply to probate assets.