Are you paying rent to live there, or is your helping your mum around the house, working the land and paying for the house upkeep in lieu of this? Your brother might think you have the better part of the deal if you’ve had a secure place to live for 8+ years. He sounds like an awful person but your mum likely loves him as much as you, even if he’s neglectful to her and cruel to you.
Unfortunately it’s really up to your mum what she does with her assets, but I agree with the others that keeping a record of what is spent on the house is important and may change how she views things. Otherwise she needs to make it clear in the will that the house is to be sold and the money split between you. It’s not fair for her to leave you to negotiate with an abusive sibling.
Contribute as much spare cash as you can to emergency savings in case circumstances change.
One thought, if your brother is not left half of the property, would he make life difficult for you and your daughter? Sometimes it’s healthier to walk away with what is left and be able to cut him out of your lives for good when your mum passes.