Well... I'm an older person myself although not as old as your mother if she's in her mid 80's! (By the way, I'm in awe of your father assuming he's of similar age to your mother & he's still working!)

Honestly, I don't know as there is much of anything you can do here. Depending in the laws where your parents live, you could try to gain some sort of guardianship or conservatorship I suppose. But realistically I'm not sure that's practical. If there are senior services organizations where your parents live, you might check with them & see what, if any, services they might be able to provide. Perhaps a person from a social services agency that serves seniors, or a government social worker of some sort might be able to make a home visit to assess the situation & determine if there is anything that can or should be done.

Unfortunately, unless your mother & father want some sort of services, or a case can be made for their incompetence (unlikely it would seem since your father is still working), or that they're being abused, I doubt there's a lot you're going to be able to do to have an impact on this situation. So much of this, though, does probably depend on where your parents live. So that may well be the first thing to check out. Where I live, there are lots of services available for seniors. But I know that's not the case everywhere.

Here are links to some articles, from PsychCentral's archives, that may be of some interest:

https://psychcentral.com/blog/8-ways...aging-parents/

https://psychcentral.com/lib/keeping...s-lose-theirs/

https://psychcentral.com/lib/aging-p...al-well-being/

https://psychcentral.com/news/2015/0...nts/80537.html

My best wishes to you...