Overnight mom soaks her diaper, bed, and then sits on the toilet urinating more. Is this normal?

Does she appear to be in any pain? I know that with dementia and advanced age, you may not want extensive testing, but, if she's uncomfortable, then, I'd explore bladder stones, kidney disease, diabetes etc. I had 2 things that made me urinate A LOT. One was just before my diagnosis of Type I diabetes and the other was just before I was diagnosed with Hypopneas. I was getting up to urinate 4-5 times per night. (It was caused by low oxygen while sleeping. Prescribed cpap, which stopped it.)

Normal? No, you are dealing with dementia, nothing is normal and each person is different. Has she been checked for a UTI?

Has she been checked for diabetes?

Is she producing a lot of urine other than at night, or just a bit? I'm wondering about loss of muscle control. Seems to happen to us as we age, and I would imagine that older people in their 90's have more muscle loss, or lack of muscle control. Just wondering out loud on this....

Is she taking a diuretic?

No UTI.

No diuretic

She produces unbelievable amounts of urine. It amazes me. Thank you all for your suggestions.

According to the Healthline website, The most common symptoms of type 2 diabetes include:
excessive thirst
frequent or increased urination, especially at night
excessive hunger
fatigue
blurry vision
sores or cuts that won’t heal

Is your mom displaying any other symptoms on this list? Diabetes is certainly not the only thing that could be causing this, but itis easy to test for -- you could even buy an inexpensive glucose monitor and test for it at home, if medical appointments distress mom. Or it can easily be checked with a medical blood draw. If she has a visiting nurse, ask them to check her blood sugars. Mom would then need to follow up with a doctor if the readings are suspicious, but at least you'd know if that would be worthwhile.