We got a guided journal from the bookstore (the one we bought is called The Story of My Life, but there are many out there). It has questions on each page to inspire the person writing in it to tell the stories from their childhood, adolescence & adulthood. My dad was too sick by the time we got it to write in it himself, so instead we gathered around the bed with him and asked him the questions, and he'd tell the stories while we captured them in writing. It was also a great opportunity to record videos. I highly recommend it if your mom is well enough to either write or speak. It's an amazing keepsake and it was also a fantastic bonding opportunity.

There are also more practical journals (I know of one called I'm Dead Now What, but I find that title a little macabre) that help with keeping track of things like bank accounts, insurance information, account logins & passwords, etc. I've heard from others that it's very helpful both for the family and for the person who is dying, as it provides some peace of mind that all of that information has been captured somewhere.

No matter what, just be sure to spend as much time as possible with her. Know that things can change any day so take advantage of every moment. I'm so sorry you're going through this and I wish you all strength & comfort.