I am looking for a word(s) that describes someone who deceives/takes advantage of an old person to get that old person to name him as his caretaker, POA, successor trustee of his trust, etc. Sample sentence: "Mr. Smith was a(n) _________ attorney who duped my Dad into signing over his assets by having him change his legal paperwork to make Mr. Smith his POA."
It's difficult to find a single adjective here that conveys both sentiments. I would suggest using the words "predatory", "propensity" and "swindling". It's not the shortest way to convey what you're looking for, but I think it works.
You could structure you sentence like this:
"Mr. Smith, a predatory attorney with a propensity for swindling the elderly, duped my Dad into signing over his assets by having him change his legal paperwork to make Mr. Smith his POA."
predatory - adjective - seeking to exploit others. "she always felt at the mercy of predatory men" synonyms: exploitative, wolfish, rapacious, greedy, acquisitive, avaricious, vulturine; rarevulturous "I could see a predatory gleam in his eyes"
propensity - noun - an inclination or natural tendency to behave in a particular way.
swindle - verb - gerund or present participle: swindling use deception to deprive (someone) of money or possessions. "a businessman swindled investors out of millions of pounds"
The established term is elder abuse.
Elder abuse is mistreatment of an older person that is committed by someone with whom the older person has a relationship of trust such as a partner, family member, friend or carer. - Seniors Rights Victoria
Elder abuse can be defined as "a single, or repeated act, or lack of appropriate action, occurring within any relationship where there is an expectation of trust which causes harm or distress to an older person". - World Health Organization
The perpetrator can be simply called an abuser.
An abuser can be a spouse, partner, relative, a friend or neighbor, a volunteer worker, a paid worker, practitioner, solicitor, or any other individual with the intent to deprive a vulnerable person of their resources. - wikipedia article on Elder Abuse
Your sample sentence would then look like "Mr. Smith was an elder-abusive attorney ...".
My first attempt:
"Mr. Smith was a senility profiteering attorney who duped my Dad into signing over his assets by having him change his legal paperwork to make Mr. Smith his POA."
In this case, you may be trading off word economy, grammar, interpretation, and most importantly, impact. I assume impact and emotional effect is the sole purpose of making such a statement.
I would carefully reconsider your sentence structure depending on context (i.e., spoken colloquially? published academically?). Perhaps you could say something like
"Mr. Smith, an attorney notorious for the shameless profiteering of our beloved senior citizens, underhandedly deceived my own father into waiving the control rights to his assets by authorizing Mr. Smith as a representative power of attorney..."
"Mr. Smith -- that attorney. Do you know what that guy did? He totally duped my Dad into giving up all of his stuff by tricking him into signing some papers that gave him the power of attorney. And my Dad is really acting old these days. What a crook! Now I have to find another lawyer just to undo what this shady lawyer did."
con artist vocabulary.com
a swindler who exploits the confidence of his victim
How about Senior Hoodwinker or combine elderhoodwink? There should be a word for such a person! hoodwink:To take in by deceptive means; deceive. OR others: Elderduper; seniorvictimizer; elderknave; Seniorschemer? THERE HAS TO BE A WORD introduced into today's society!