I am so depressed with my elderly mum's negativity. How do I cope?

Thanks SO much for replying. You give me so much hope that there is someone out there I can speak to .
@Alvadeer you are so right . I DO feel My heart pounding out of my chest ... constantly down , feel numb , SO tired ...
I will try , I will ...for the sake of my own sanity , my relationship with my husband , my kids concern for my well being ....
I don't have a life at the moment but I am going to try and change this situation for the better . It won't be easy

Please forgive me in advance because I tend to speak very plainly.
You say that your mother has such a strong hold on you and your brother that the two of you can't stop tolerating her abusive and belittling behavior. You also say she has pretty much destroyed the self-esteem of both you and your brother.

You're 60 years old. You have your own family. You live in another country.
Cut the cord already.
Your mother's a bully. The only way you or your brother will be able to have any kind of relationship with her that isn't toxic and unhealthy is if you stand up to her for yourselves.
When you are talking to her on the phone and she starts up tell her you don't want to hear it and hang up. Then don't take her calls until you choose to talk to her again.
Stop visiting her every three months. Tell her exactly why. That is because you cannot and will not tolerate her negativity and abuse. She will probably get the picture if you start hanging up on her when the abuse starts. When you visit her next, make sure you have a plan 'B' so you don't have to stay with her if she's being abusive.
I didn't see or speak to my mother for almost six years. One day I decided that I was done with her crap. The verbal abuse, gaslighting, scapegoating, belittling, and bullying had gone on long enough. I didn't even have her at my wedding. She ruined my first one with her negativity and belittling of me and I learned from it.
As she got older and needier I started speaking to her again only on the phone at first. If she started up, I hung up on her.
I'm her caregiver and live with her now. Things aren't so bad because I tolerate nothing.
No stubbornness, no gaslighting, no negativity, no instigating, no complaining. I don't play the doctor game with her anymore either. She was famous for sabotaging and ruining special events. I had a lifetime of this. She tried once since I came back. A staged health crisis because I had planned to go to a wedding and would be gone for the weekend. My response to her was I'll call 911 and I left for the wedding. There wasn't anything wrong and she never tried it again.
This is how you and your brother have to start being with your mother. Stop tolerating her crap and stand up for yourselves.

Seek help through counseling. You say that you have been (well) advised to limit calls and perhaps visits, but you "can't". You seem to understand that this would be best for you, but something, perhaps your Mom's own expertise at "guilting" is stopping you. You need the support of a counselor who is trained in life transitions; that's often specially trained Licensed Social Workers. You are reacting with anxiety that, indeed, CAN harm you with a rise in cortisol, adrenaline, epinephrine levels; these fight or flight responses aren't good for any part of our body and I would bet you can literally FEEL your heart pounding, your stomach dropping out, your brain robbed of oxygen levels.
When your own self-knowledge and the advice of others isn't enough, run, don't walk, to seek a counselor to help you.

https://www.agingcare.com/questions/how-to-cope-with-emotional-blackmail-of-my-narcissist-elderly-mother-473909.htm

You asked a similar question on the 27th and received some good answers. One being you need to do is set Boundries. You have a brother who you said lives with her. So she is not alone. I think this is a cultural thing and if you lived closer you could give her more time. For someone who lives 4000 miles away, though, I think its crazy to expect that you should be there for her. As I said in ur last post, I think you do too much. You need to be firm with Mom and tell her "I am sorry, but I can't do this anymore. Mother, you need to realize that I have a husband and family I have a responsibility to. That I quit a job so I can see you more often but, I am finding that its exhausting to fly back and forth and staying for the length of time I do. Really, I think once a year for 6 weeks is enough. 2x a year for a month is enough.

My husbands grandmother, back in the early 1900, moved from Sweden to work in the US. She met DHs grandfather and had 8 kids and raised a grandson. She never saw her family again. Your Mothers expectations for you are too high.

You are not a bad daughter.

dear OP,

HUG!!!!!!

i repeat what Barb wrote:
"You don't raise up a child to be your servant; you raise them up to go out into the world and pave their way."

You need to seek therapy if your mother's unhappiness is affecting you in this way.

We are each responsible for our own happiness and can only control our OWN behavior.

Your mothers demand are UNREASONABLE. You don't raise up a child to be your servant; you raise them up to go out into the world and pave their way.