Mom won't listen when I tell her something for her own good but she'll listen to non existing caregivers (brother and sister). Any advice?

I think it may be the effect of hearing something from more than one person. They can dismiss the advice if it's "just" us; but when they hear it from multiple sources...well, then it's good! What I do is I email my cousins and brothers with what I want Mom to pay attention to (fall prevention, washing her hands after bathroom, etc) and have EVERYONE tell her the same thing. Sometimes, it works!

I can't explain the why of it. My mother is the same way. I can tell her something and she won't believe me If my brother, SIL, or even my 14-year old nephew tells her, she'll accept it. I don't let it bother me, because I believe Mom needs to see me as not so smart. It's one of those things I just rolls my eyes at and go on.

If that were only that easy. Mine can agree when someone besides me tells her something, but goes back to disagreeing when it is just her and me. No, it's not pleasing them -- she just forgot that she agreed.

Nope. You just happen to be convenient. If they were the ones caring for her day to day, she wouldn't listen to them either. It may be her way to "stay connected" with them and she feels they are not around much and if she doesn't take their advice they won't give her the time of day.

She knows you aren't leaving and can speak her mind knowing you aren't going anywhere.

If you can't ignore it and it gets under your skin, nothing wrong with confronting her and saying "Mom, it really hurts me when you listen to Sister Carol, but you won't listen to me when I give you dip same advice? -- why do you do that mom?". Then repeat same mantra every time she does it.

Tell her that maybe she should love in with Carol since Carol seems to know what is best.

That may curtail it, or at least make you feel better.

I meant ...live with Carol..." Butter fingers on the keyboard...

Be glad they are on the same page with you and use it to your advantage. Parents will dismiss a child, but if ALL the children can somehow agree and stand together on an issue, she is more likely to give in. When we took mom's car away, she quickly found out that not one of the three children would get it back for her. Game over.