Father has Alzheimer’s and his wife has him against his own children who are POA/conservator and guardian. He is refusing all care. Advice?

Dad and wife have NOTHING in their name together. It’s his house- his name only. Her house in her name only. All Separate bank accounts too. Dad has trust set up since 1996. She has home to go to if she gets evicted. I just want to have iron clad case and evidence before proceeding with the attorney/ court once as his permanent guardian I’m fully expecting. Dad wants to stay in his own home- to die- he hates being at her house. She is in the way of his needs- and willfully acts and speaks -to his detriment- preventing him from a calm emotional well-being- and all the good things that could be possible for him. It’s a difficult time period and about all I can do is watch and continue documenting my efforts and her interference with and abusing him thru his dementia weakened mind causing him to refuse needed care and intervention.

as dgt, 43 year an RN, performing all his health care needs since 2018, seen his cognitive decline, much more decline in past 6-9 months, was in process of starting mental eval when Covid hit, was able to get neuropsych eval in June 2021 showing moderate dementia and primary dr eval from April 2021 concurred, was awarded emergency guardian,& brother ( acting POA and full manager of real estate income over 10 years, and all personal and business finances past 2 years) as conservator in July after being notified she drove him to investment office for full withdrawal, he was on Vulnerable list so we were notified and financial offense did not occur. Court evaluations now concur he needs full conservator & guardian. Brainwashing him began several years ago by telling him and all ( even us!) that we were stealing all his money and he needed to give it to her in her name and bank only, to ‘protect it’. She’s told everyone for years she expects to get 1 million$ so she’s created this false narrative to him and used his dementia as her weapon against us. wife knows she’s been caught red handed and has spun this upon my dad currently violently verbally abusive to us every time we go there- every day- making him believe her ( no doubt need to be a fly on the wall to hear frequency and intensity of her slanderous behavior) to turn him against us, and all our efforts to complete medical work up appts, home care giver, to not be refused, ( he’s lost 30 lbs over last few years). Pretty much everything she is accusing us of she is actually doing to him herself- not us! He’s gonna need $ for full care for likely many years to come ( no serious medical issues- just brain)
and we intend to use his money on his care- inheritance will result if anything is left but no counting on it - just trying to do best for him and help him be happy and healthy in these last years. Oh- he’s dalready ‘set her up’ with 3/4+million$, house, car, etc etc. and she just wants to make us miserable since she’s been caught and the $ faucet is turned off! She walked out on him 2 years ago- he let her go too- but she said she’d return if he gave her money- he cashed in and gifted her 4 huge accounts then… so just collecting evidence now til there is enough to get her removed or press criminal charges if necessary.

Not yet- things I’ve read say this is the most difficult to prove and must have evidence- but I’m not sure exactly what constitutes their definition of ‘evidence’. She is vindictive toward us and uncooperative but it is also to my dads detriment- she got caught- took dad to empty all his investment accounts w/ check to her. She has brainwashed him to believe we are stealing from him and living in his house he is cognitively & emotionally vulnerable- made to believe he’s dependent on her- they both would totally lie to APS- who would see between the lines in this situation without evidence? And what kind of evidence is admissible?