We lost my dad a couple of weeks ago - he lived with dementia for about ten years. It progressed steadily and at the end it was severe - for example he was doubly incontinent. Nontheless, he still had lucid moments where he knew us and was able to talk to us.
I would say it got easier over time, because we became accustomed to it, and learnt to treasure the good times?
We were lucky in that mom was able to care for him at home (I moved across the country and bought a flat about 5 minutes away from them to support them in the final years).
I would advise anyone in this position to spend as much time with their relative who has dementia as they can, talk to them as much as they can, give them as many great experiences as they can..... Loving human touch is also important and powerful in this scenario I think.
When dad finally passed it was in his own bed. I was next to him and had spent the whole morning by his side, holding his hand and talking to him. My brother and mother were also at hand, and mom had spent the night lying with him, her last night with her husband of 50 years.
He may have lost most of his faculties, but he did still know that he loved us and that we loved him, I am convinced of it.
Make the most of what you have, while you still have it. And I am, of course, so sorry for your loss.
If anyone has any questions, please DM me. Especially if you would like to know more about letting a relative with dementia die at home with only palliative care. I don't want to post too many details as they may be distressing for anyone who is not in that position - but equally I think it's something that people need to go into open eyed, if they do make that choice.