Hi
@Harbour
It's very thoughtful of you to try and help your cousin, which I am sure she will appreciate.
Here in East Kent, we have a few carer support organisations, one of which has been extremely helpful, especially in the early stages, following my wife's diagnosis back in 2014. They offer a dementia visitor service of 3 hours a week. We had to go on the waiting list, which took around 9 months, but for the last 3+ years, a lovely lady has been sitting with my wife from 13:30 to 16:30 every Monday. This service is free (they are a charitable based organisation), so I make an annual donation, to help them continue their great work.
If you haven't already done so, try searching online for dementia support in your cousin's area. Even if her husband is reluctant to go to day care etc, support groups are often great places to start exploring what help is available. I managed to get my wife to go to a local dementia coffee morning. Though she didn't get much from it, I gleaned a huge amount of information, just talking to other carers, including information leaflets from various organisations.
I hope your cousin gets on okay.
Best wishes.
Phil