I'm in the US and we do not have such a law.
My mother had late stage liver cancer and was in the hospital when she told me "this is not a life" and that "she was ready to go."
At the time, most of her liver was tumor which was causing her to have hypoglycemic episodes that had to be managed and the tumor size was such that she felt constant pressure on her other organs and particularly her back. A glucose drip helped to maintain her blood sugar levels, but even with that there were times when it would drop precipitously.
Overall, she was lucid and in relatively good spirits considering, but it was only going to get worse and it was not something to look forward to. And with all her affairs in order, she was at peace with it.
And I certainly didn't want her to suffer any more than needed.
Fortunately, even though euthanasia is not allowed, this case did allow for something similar.
We would transfer her to a hospice. Since she had the right to refuse any treatment, we could have the glucose IV removed. Her blood sugar would then drop and she'd eventually pass on.
In addition, the hospice would give her lorazepam to ease her during that time, so in implementation, it really did feel like an assisted death.
The actual moment of death was quite amazing.
The lorazepam and the glucose removal was not an instantaneous death, instead she just fell off into a deep sleep and lay there and we just waited for the eventuality. A few hours later, my sister and I noticed just a little movement with her and we took position at either side of the bed. We each took one of her hands and held onto her.
I then said to her "It's ok. You can go now."
A moment later, the limp arms suddenly filled with life and strength, and pulled our hands up to her chest. Our hands were all together for what seemed like an eternity. Then the life ebbed out and the arms fell back to the sides of her body and we let her go.
As with you, it was a hopeful and positive moment and not a despondent one.
Because she was able to go in peace and on her terms, it was easy for us to say the final goodbye. There were no tears at that time (those had come much earlier), but instead, we could breathe easy and move forward.