I went from 0 to 100 and I'm in way over my head.

I'll try to make this as short as possible. I appreciate any insight you can provide. My family lives in Michigan, I moved to Canada. I've been estranged from the family for almost a decade due to issues with my father. My father passed away about 6 months ago and I returned to support my family for the funeral. Upon getting home I realized my mom was acting strangely. She was having a hard time getting around, asked about friends I never had, had gotten herself into some legal trouble (civil, not criminal), was months behind on her bills, and so on. Over the last 6 months we’ve been working on putting her life back together. We helped her relocate near a place where her horse is being boarded so she wasn’t driving 3.5 hours a day to check on it for 5 minutes (she has issues with paranoia, people wanting to hurt her horse or her dog, etc). We got her bills up to date, dealt with financing, doctors visits, medication delivery, etc. But in the process she has been almost completely unwilling to help us with anything. She can and does feed herself and her dog, she does have some basic hygiene, but that’s it. She also seems to drive fine. Anything beyond that and it’s a no go. She can’t manage her life. She can’t keep a clean house (to what extent I’m not sure, I’ve been told it’s less than sanitary). She’s not compliant with her meds. She won’t even check her mail so she can pass off pertinent info to me so I can stay on top of her bills. There are issues where we will ask her to do simple things that are obviously in her best interest like simple banking, paying rent, etc, but she simply doesn’t do it. It it’s not part of the basics of survival, it’s up to my brother and I to detect it and act on it. The big question that we had up until recently was that we didn’t know if she “couldn’t” take care of herself, or “wouldn’t”. We get some neurological workup and a cognitive assessment. She has mild cognitive dysfunction, but scores in the normal range. As far as we know there is nothing anatomically wrong with her brain. The next step is to try to get a psychiatric workup done. It should be noted that my mother and father were divorcing at the time of his death and she seemed completely unphased by his death, so we don’t know what if any contribution that adds to the current issue. The place where she’s living in right now is a manufactured home of her choosing that she loved and thought was very convenient until about 2 weeks after she moved in and then started talking about how much she hates it. The good news is that this was supposed to be temporary, we all know that, the lease expires in the Spring. The bad news is that it was her plan to use her savings to buy a house, get land, get a barn, get a pair of horses, some dogs, and live out the rest of her life tending to the animals. This is something we are absolutely convinced that she can’t do. She can’t take care of herself, there’s no way she could take care of animals, nor does she have the financial responsibility to take on something like this on her own. It’s also more than my brother and I can help her manage. We’re trying to figure out what kind of care my mother needs. How we can protect her from herself, etc. Everything up until this point has been reactionary to the “situation of the day”, but a lot of fires are out now and we need to plan for the long term. We really have very little idea of what we can do, or even if we can force her to do anything (or not to do something) given that she has passed a cognitive assessment. Again, any insight you can provide would be greatly appreciated. I doubt I’m the first person to run into a situation like this and I just need some advice on how to proceed from those with experience. Thank you.