Hello, I am so sorry this is happening.
Have you asked for a carer's assessment to get support for you? If not, social worker can organise.
Also, there was a point where my dad had to call the social and the doctor and say he just couldn't cope any more, and that got him some help.
Don;t be afraid to ask. it may not be what he wanted, but he isn't really himself any more. Focus ion safe, and as healthy as he can be; don't fret about happy, content may be what you get on a good day. And that's ok.
It's ok, and normal, to grieve for the loss of what you had. Let yourself be sad, sometimes. But do also get help.