Property in probate sold at auction; who owns it?

Hi, thanks for helping. My brother-in-law's mother passed away about a year ago (California) without making a will and he's the only heir to her property. He's living in the house but let the mortgage slide, and the bank foreclosed and sold it at auction in January. According to the court, however, this is an illegal sale because the property had not gone through the probate process. If indeed the auction sale was illegal, does the auction buyer get his money back? Is the property owned free and clear by my brother in law? What happens?

[AFFA]

I wish to inform you that if the house has been sold then court order may be taken to regard the sale as void. In this as the process taken by bank is not correct therefore bank can be held liable to compensate the buyer. The bank can foreclose property only legally and any sale without following provisions of law is a void sale and is therefore a nullity. In this the court order that sale is void may be taken and property ownership may be taken by legal heirs. The buyer of the house is not having any title from a void sale but can have compensation from bank for unjust enrichment taken by bank.

AFF

So, if the auction sale is null and void, does the bank still own the title, or is the title now free and clear for the living heir?