Legal Question in Real Estate Law in California

The senior lien collects first, then if there is any excess the next most senior, etc. It is very likely that the first loan exceeds the fair market value of the house, so that you will get nothing. Sorry.

File a lien? Even if the house is worth a jillion dollars, you can't file a lien.

Liens can be filed by so-called "mechanics" (workmen, materials suppliers, or equipment suppliers) doing a work of improvement to real estate. Liens can also be filed by tax collectors like the county and the IRS. Liens can be filed (recorded) by the consent of the parties, as when the owner takes out a loan. If you sued the friend, won, and got a judgment, you could create a lien by recording an abstract of your judgment.

It is also possible to tie up property before getting a judgment by filing suit and promptly moving the court for a writ of attachment. This is a complicated processand not advisable where the property is under water due to its market value being less than prior liens.

An ordinary person merely claiming to be a creditor cannot "file" or "record" anything to create a self-help lien.

As the previous answer indicates, liens are honored in seniority order, based upon when the lien was recorded. All claims recorded prior to yours would be paid in full from proceeds of anyone's foreclosure. In your position, your lien, if you could get one, would probably be so low in the pecking order that there's be no money left when your number came up.

You have no 'lien' right unless you sue and get a judgment to record as a 'lien', and it would be 'behind' any other prior liens like the mortgage and taxes. You might be able to get a pre-judgment lien on the house after filing suit, since you are claiming an interest in the property. But, if the house is being foreclosed, there probably is no equity in it to collect from, which would make any lien pointless. You should try to get a judgment against him, and hope he doesn't go bankrupt and wipe out yuor debt. Feel free to contact me if serious about doing so.