My 94 year old mother keeps doing things around the house that are unsafe for someone with her mobility issues, though we are here to assist. Any advice?

Try to anticipate what she is going to do: remove step stools, ladders, hide extension cords behind furniture, sharp objects need to remove. Tell mom that when she needs these things she needs to call you so because they are at your home. Or lock them in the garage and keep the key with you. Check on her day and night. She will be disrespectful because she does not know the difference. Not the best thing in the world - I was the worst daughter in the world while taking my daddy to the doctor and making sure he ate and had a clean bed. But he yelled and cursed me for about three years. Not all the time but when he did not get HIS way. I just learned to live with it because I knew it was the disease and not his true feeling. This is what we need to remember. She will soon need to be in a facility so be prepared for that. If you can hire some one to come in and assist then do that - just a suggestion do not ask her if it can happen just bring them in and introduce that person as a friend and let them start cleaning, doing chores as you sit there visiting with mom. Then soon they become friends and she may or may not accept that helper. But you need to try. Blessings to you.

I hate to say this but...
There is not much you can do.
You can wait for some catastrophic event that will limit her mobility more and possibly place her in rehab and eventually in Long Term Care be that Skilled Nursing or Assisted Living. (or caregivers in her home)
Now if you were to have indicated that mom has cognitive issues either diagnosed dementia or just "MCI" (mild cognitive impairment) you, if you are her POA might be able to have her placed in Memory Care but you do not indicate there is a memory problem. So the fact that she is cognizant you are limited as to what you can do.
I am not quite your mom's age and I also do things I should not do from time to time. And I can tell you that it is because
1) I can be stubborn.
2) I hate asking for help. My daughter works, her husband works and the eldest grandson is in college, they are all busy the last thing they need is a list of things to do for me.
Part of asking for help is the admission that you are getting older and no one wants to admit that.

The one suggestion I have is pick a day of the week. Whatever day is easiest for you.
That day will be "mom's day"
Go over that day and do some of the stuff that needs to be done. If nothing needs to be done spend a bit of time with her just talking. Maybe she tries to get things done so when you do come over she can spend time while you are not busy doing things for her.

Tell her you’ll be there every week on the same day and she should add things to a list for you to do when you get there.

This is unlikely to work. She probably has some cognitive decline as evidenced by her personality changes.

"She refuses to accept that I am two houses down and a phone call away for anything that she needs done".

May I suggust that there are connections (assumptions) made in that sentence that maybe your Mom disagrees with?

"She refuses to accept that I am two houses down.."
Mom knows where you live.

"and a phone call away.."
She knows that too.

"for anything that she needs done".
THAT. Stop there.
She doesn’t WANT you to do it.

Hence the anger.
No-body likes to be bossed around, made to feel old or useless, have their daily work taken away.

I'm sure your intentions are good - Safety.

Maybe discuss with Mom what she wants to stay independant with, what chores she would like to do with someone's assistance & what tasks would be sensible to delegate.
Eg Choose her grocery items, light dusting independantly.
Order groceries with someone to help, wash the clothes with help.
Delegate grocery delivery.
Delegate mopping floors.

Anyway just ideas.

If Mom has become like a teenage risk taker, up ladders or walking alone at night you have a very different situation.

It is here, on this site, that I learned to NEVER ask anyone for help. Doing so comes with criticism and disrespect. NOPE, I will pay someone before ever considering asking family for help.

Do yourself, your wife and your mother a favor by hiring a helper/companion like a "Visiting Angel."

I have found that elderly people LOVE to climb on stools and ladders! It is maddening!

She has taken care of herself for a lifetime and perhaps isn't interested in giving up what she perceives as her independence. I'd be interested in an example of what she is doing that you feel is unsafe, that will make it easier to determine whether you are being a helicopter son or she is truly being foolish.

If she has any history of being someone who tries to make other people happy, you might appeal to her with the ploy that helping her makes you happy and makes you feel important in her life. That way, SHE is giving YOU a GIFT by allowing you to help her. Then it's not about her ability to do things anymore or about safety, but about improving your relationship with her. It's about reframing how both you and she view your offers of help. May or may not work, but worth a try....

What kind of things is she trying to do? Unless it's terribly unsafe, it's good for her to stay active. But there is a line between active and doing what she's always done vs being unsafe.

You don't want to become her go-to for every little thing. It's unnecessary and will create burnout really quickly.

Mom being disrespectful to your wife could be related to cognitive decline or dementia. I think you and your wife should assume that and not take it personally. If you think it's intentional, then look into boundary setting to help her cut down on it.

Best of luck.

paulbruno: Unless she is doing things that are harmful to her body or presenting a slip and fall, perhaps she doesn't require the help that you perceive. Best of luck.