This link may answer your question. Foreclosure law and right of redemption in California is different than other states. So I caution you to read up on California Law instead of relying on out of state responders if they are not familiar with our laws here in California.
The law here is very specific. A Notice of Default is recorded, It must be Posted and notice given in the paper. Your have time lines to follow.
You may want to try to work something out with the owner, perhaps pay the taxes and add it to the loan and work out a re-payment schedule. Check that they have maintained home owners insurance as well naming you as additionally insured.