Independence diminishing. Any recommendations?

The prompt I use for DH is tell him to push; it's time for poo. This seems to release whatever muscle for urination.

Yes, we went through this too. Now mom doesn't even have any awareness of urination. Earlier on I could sit her on the toilet , every 2 hours, for a bit and she would go. Then slowly she just quit going "on command". I think each person is different. Just keep trying...run the water... Give her a prompt, etc

New, very challenging to have a young mom with dementia. This disease works in strange ways and leaves caregivers hustling for new solutions. The therapist that worked with my Mom taught me to use cues. You can try to accompany her more, get her attention, and cue her on what you want her to do. Make sure you have her attention, keep instructions brief and direct. "Mom, I'm helping you into the bathroom... Now sit down over here. .. OK, now relax and let the water come out of your body.
I needed to cue my Mom on how to walk! I would tap her leg and say ok Mom, move your right leg, now the left, right, left, etc. During a visit, my cousins, laughed and said I sounded like a drill sergeant. They had no idea that she needed the reminder.
Sometimes these changes are short lived, at other times they become a part of the routine. Good luck