To know what process is available to me on his behalf (from a legal point of view), and to get my notes in order for a meeting with his estate planning attorney (who believes fixing my father's "mess", as his attorney has said, will cost my father more than the original trust document fees of $3500). Please allow me to explain the path I need to take from your last input.
My father and I have come to agree making me his confidant as sole trustee (him as beneficiary), giving me enduring power of attorney, amending his existing trust as irrevocable after these necessary changes. Additionally, he will cede control volunteering himself to be declared incompetent to manage his own affairs (if it is legally possible to volunteer this). Hopefully in doing so, it will avoid him making consistently unsound and irrational decisions.
To the extent of having himself declared incompetent (either by volunteering or by process, i.e., by psychiatric exam, etc.), perhaps a "Living Trust" is no longer warranted because he no longer has significant assets. Perhaps considering making him a very simple estate plan showing him as my "ward", or my being named as his "permanent guardian" would be more suitable. I don't know? I am walking in no-mans land on this.
Please understand, my father feels he can no longer make good decisions and feels he makes the wrong decisions, and feels his choices have caused him personal and financial harm, and he does not trust his own abilities. My father is fundamentally incapable of making sound decisions.