So sorry to hear of your situation, (and the other posters too) and especially being at the other end of the world! That must be so hard!!
I'm a bit similar, but it is my mother who has dementia (about 5 years already) and it was really hard on my father, she wasn't physically aggressive, more very passive (lying in bed all day), and bitchy, which was awful! My dad deserves a medal for never losing his patience with her and taking it all in his stride! He did everything for her.
She's been in a care home for about a year now, not too happy there, but being well looked after, so that is reassuring anyway.
She phones up all the time tho and says "I'm coming home tomorrow" i.e. for good, and says "I can look after myself!" (which she can't), she's already had a couple of falls that landed her in the hospital.
My dad is now in hospital with cancer and related conditions, he is dying basically...

We also live in different countries, but luckily not at the other end of the world, all in Europe, and flights are cheap to hop on, and only a couple of hours away, I'm spending more time there than here nowadays.
I have a son - am a single mum - but he is 19 and can take care of himself, with strict instructions not to throw any parties :o
Wishing you all lots of strength in dealing with this difficult time!