After your dad passes away, invite your mom to live with or near you. She deserves happiness in her life.

Your mom may not be able to care for him physically much longer. She's also at risk of physical injury herself, either because he falls or because he becomes physically abusive as his mind deteriorates.

I think the best thing you could do would be to get him into a memory care facility, assuming that's financially feasible. NOT one where they live together. She needs to be free to live the rest of her life without his abuse. Maybe she's too codependent to have any independent will left after enduring his abuse for years, but she's never going to find out if she doesn't get away from him.

I also don't understand how you can describe him as a loving dad, frankly. Maybe also some therapy for yourself?

I don’t think your dad abusing your mom in your presence is being a loving father. Nonetheless - there’s little you can do at this point; your mom is making her own choices for her own complex reasons. I don’t know what support is available in their country but you could find out and encourage your mom to utilize them. You can also acknowledge how difficult her situation is and exoress your love and support, although there’s only so much you can do from afar.

OP, it's very hard to get help or to see clearly from within the fog of being abused. Your father's medical condition makes things much worse, but also may progress such that your mom is no longer in a position to care for him.

My mom "woke up" and decided she wanted out of my dad's control and financial abuse in her mid-70s. TBD if she will succeed. The best thing you can do for your mom, IMO, is support her verbally while maintaining whatever boundaries you need for your sanity. You cannot make her want what she doesn't want.

A good book about abusive men that seems to truly care about the experience of women who are in their lives is "why does he do that."

That was my dad. I don't see him as loving father because of the abuse. I felt the abuse my mother endured.
I don't think you can do much if she doesn't want help. Mine got divorced luckily and will be fine on their own as state helps with the elderly.

Invite her to live with you since she is no longer working anyway.

Does she need money?

I'm an only child who had a nice and loving childhood. My father was a wonderful dad, but he has always been horrible to my mother. Belittling her, gaslighting her, emotional and financial abuse. He had a terrible childhood himself and I suspect his father treated his mother in much the same way.

He's only 67 and in excellent physical health, but he's quickly succumbed to dementia. My mother (70) has had to give up her job to look after him full time, which sounds exhausting and miserable. He's often absolutely horrible to her, refusing to speak to her for days, blaming her for everything (he was also like this when he was well). I've tried to encourage her to get help and look after herself, but she brushes off my suggestions. How can I offer more specific suggestions that she might take up?

I can't offer any in-person help as I emigrated many years ago and live overseas with my young family.