Legal Question in Real Estate Law in California

You should at least get a promissory note reflecting the terms of the loan. When is it payable if the home does not sell? Is it now listed, or is this to be paid if, and when, she sells in the future? What is the interest rate? When is interest payable?

You do not necessarily need an attorney to draw a note of this nature. If you are not comfortable in doing it yourself, there are many forms on line. Things get more complex if you want a security interest, which would require a deed of trust on the home. Do you wnat security? Do you trust your mother to pay this. What about if she is then incapacitated or deceased? All these issues and your decisions determine what should be done to evidence the debt.

At minimum document the deal with a written note.

I agree. We lawyers see plenty of disputes based on loans or similar transactions between family members where something has gone awry, sometimes as simple as forgetfulness, sometimes as nasty as a change in how one family member feels about the other.