OP,
You can't pretend you don't know and you can't pretend you don't have a choice in this.
Your mother has choices and so do you.
You have agency here but if you choose to accept this and carry on, you have no one to blame but yourself.
I am late 50's and have come across this over the years.
You will never get over this, if you accept it, and it will sour to nothing your relationship with your mother and your life if you try to suck it up.
It will be a blight on your life and when it comes to elder care you will likely become ill in yourself with the annoyance and anger.
Offering it up and thinking it will be ok will be the most foolish thing you can do.
I would suggest you focus on your children and family and perhaps look at the practicalities of moving for his job.
Let that be the reason for the move, the job that provides for you all.
You have to protect your children and your family life and this type of treatment eats away at people.
My friend had a golden brother who got everything and even wanted paying for a site of land that she had always been assured she would get.
She upped and bought a house 35 minutes from her parents and raised her children in the city.
Her brother never had children and despite offers of free sites after she bought her home etc., she never backed down.
She has never regretted her choice and her parents now pay for care as she is completely uninvolved.
She sees her parents ever month as with FT work, sporty children etc., life is very busy.
Another friend was very hurt but sucked it up and moved on, or so she thought.
Her mother broke her hip in her 70's and she decided actually No, she wouldn't be coming to stay with her, she could pay for residential respite care for 6 weeks.
There was drama but her husband said he was happy to be the fall guy as he did not agree with her reducing her hours to mind her mother who was also leaving everything to her comfortably off bachelor brother.
It was the best thing she did for herself.
She still sees her mother but ALL care is paid for by her, including all maintenance of house and garden.
Ten years on, that friend has moved on from it in a very healthy way.
She feels no obligation to her mothers care needs.
She doesn't have to worry about holidays, and can focus on her family.
Her relationship with her brother hasn't survived as he pushed back hard when the hospital wanted to release her to her daughter.
He absolutely believed it was her duty to take her in.
If she had, she probably would be still there now.
She is hugely thankful she didn't as her mother is demanding and cranky.
On balance she is happy to forgo her inheritance as she believes her mother living with her would have been very trying.
Don't try and suck this up and push it down, the unfairness will drive you mad.
Far better to say at a time that suits you, thats fine mother, but upon reflection I too will be making choices that put me and my family first.
She doesn't owe you an inheritance and you most certainly don't owe her elder care.
I do not believe in unequal treatment of children regarding inheritance and I don't believe in sucking it up when you are treated poorly.