If you believe there was abuse, then you can report it anonymously to the County Adult Protective Services Agency in the county where your friend lives. It sounds, though, as if that might already have happened if the trustee and the neuropsychologist were "removed".
Here's a link for the Santa Clara County APS: http://www.sccgov.org/sites/ssa/Department%20of%20Aging%20-%20Adult%20Services/Adult%20Protective%20Services/How%20Do%20I%20Make%20a%20Dependent%20Adult%20or%20Elder%20Abuse%20Report-/Pages/Adult-Protective-Services---How-Do-I-Make-a-Dependent-Adult-or-Elder-Abuse-Report-.aspx
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As I see it, you lack standing here to make complaints about anyone involved on any basis. Exactly what the State licensing agency already told you. Unless you have been appointed conservator for your friend, under the law you are entitled to no confidential or personal information about your friend or your friend's cases or legal matters, and you have no legal standing to interject yourself into any of your friend's legal or medical (psychiatric or psychological) disputes or issues.
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My colleagues are correct. Unless you have a legal tie to your close friend, you lack standing to make complaints on his behalf. As for filing another complaint about the former trustee and or the neuropsychologist, you could make an anonymous complaint. Good luck.
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