I am so sorry for you both. How frustrating it must be! Have you trying seeing a naturopathic physician. They utilize many things traditional western doctors don’t and if nothing else may be able to help with some of the symptoms.
Depression can come from the body being so depleted and worn down. A Naturopath can provide nutritional support through IV in the office and supplements that you can not get over the counter.

For example, my mom with PD and Lewy Body Dementia just came to live with me. She had previously lived with my sister for 3 years, and had gotten to the point where my sister hired 24 hour care. My sister had stopped all of her supplements, and never started a fish protein supplement and glutamine powder prescribed by her naturopath. She had given up. But she was taking all of her traditional western medicines. But had fallen twice, injured her arm, needed help walking, was sleeping a lot, confusion, hallucinations, trouble waking, etc.
I put her back on her supplements and started the fish protein and glutamine powder. She has been with me 3 months. She is independent with stand-by assist or Walker for walking. She is sleeping well, about 10 hours per night, and her appetite has improved. She no longer wants to die and has a routine.
Let me say we had tried many things before and some helped a little and some not at all. But this clearly ended up being what she needed.
Don’t give up, look for alternatives, hopefully you can find a naturopath in your area that can really help!

I see a holistic practitioner and she has me on a regimen of supplements that is modified every two to three months. Before I began the supplements I had memory issues and was told by my doctor not to drive any more. I've been on these supplements now for about six months. My moods are much better and am driving once again. My wife had taken over bill paying, but I'm back doing our finances again. I feel so much better now. So yes, a natural path is a very good option.

Don’t give up. Sometimes it helps to see a Neurologist that is also a movement specialist. I know it has helped me when the neurologist I had been seeing appeared to loose interest and run out of options. The neurologist/movement specialist has changed one of my prescriptions and added two more. I feel like I got my live back. I know this important is only temporary, since Parkinson’s at this time has no cure. But who’s to say that a cure could not be found in my lifetime. But even if that will not happen. I will celebrate every day I can still do at least some of the things I used to do. Good luck on trying a new neurologist. Don’t give up. God bless you and your wife.

Something’s not right. She should be on a low dose antidepressant and see how she tolerates it. There are different classifications of antidepressants and she needs the right one. I’m not a doctor or pharmacist but there are specific meds based on your condition.
My doctors at Hopkins had me change my antidepressants as they were interfering with the meds they were prescribing for my neurotransmitters. A good neurologist specializing in movement disorders would help.

If there was a God there wouldn't be these terrible diseases.