Best ways moisten dying loved one's mouth?

KY jelly. Frequently used.
if oxygen is in use, do not use Vaseline or lip balm products as they can burn the lips when O2 is being used.

There are swabs intended for this.
Some are plain some flavored.
You moisten the swab and place it against the cheek and run it around the inside of the mouth.
Be cautious when going into the mouth to get the tongue as the person may bite down and could bit a swab in half. (most have a plastic handle so it is rare this occurs) Do not use a long swab with a wood handle as that can easily be bitten.
Do not use ice chips as that can cause aspiration.
Is Hospice involved? If so ask the Nurse for swabs, I am surprised they would not have given you some.
If Hospice is not involved give them a call. They will be of great help, even if it is for a short time.

Lemon swabs worked for my mother. I think they were purchased in sterile packets. I’ll Google them and post back.

If your LO is under hospice care, they will supply you with the little sponge things on a stick(sorry I can't remember what they're called), that you just moisten with water and then can put in your LO's mouth.

One of our hospice nurses suggested that I make ice chips from my dad’s favorite drink and spoon them into his mouth a little at a time. It’s worked great! He loved the flavor and always opened up for them. I froze the drink in a thin sheet just a bit at a time in the freezer and chipped it apart with a spoon.

There's a long stick with a tiny sponge on it and you wet it and then run it through and around the mouth and that works well to help moisten the mouth.
Maybe the pharmacy sells them or would know how to help you with this or have some other ideas to help you.

Dear "Jul1925,"

You can go to healthinfo.org.nz and click on "A-Z health topics."
Then go to "M" and look for Mouth care in palliative care for tips.

When my dad was under hospice care back in 2004, they had some sort of sponge stick that they would dip in water and swab his mouth.

I'm so sorry you are going through this with your loved one.

You'll be in my thoughts and prayers - take care!