My dad just got diagnosed with Alzheimer's. He is in charge of all of the finances. Does my mom have rights as a spouse?

I would suggest that your mother has a durable power of attorney. It requires a lawyer and it is best to have one experienced with elder care. I had to get this for me dealing with my mother. Without that you could be entering into a host of problems. The proper lawyer would speak with your father in a manner that could be helpful.

Auto pay was a blessing. Best thing I could have done in their interest, after bills were being "missed". Do that, if possible. Now it's great for my mil.

Does mom have a social security check? How is it managed? I’m sure that is not a long term solution but perhaps enough to pay the utilities.
She needs an appointment with a certified elder attorney to find out how she is protected by the laws of her state. Community property and all that.
Does dad have credit cards? How does mom buy groceries? Does he give her cash? She can take that money and use it for utilities and tell him she needs more for groceries. Whatever will work with him.
She will be under tremendous stress dealing with him and trying to figure out how to “keep the lights on”.
This will of course create other problems.
My MIL was on the bank accounts etc but was so hesitant to pay a bill when FIL was in the hospital for months that it was exasperating. Long term conditioning had taught her to not interfere. We finally got her to sign the checks if someone else filled them out. So I’m thinking your mom might not just accept that your dad can no longer be in charge of finances. If this is completely out of the question for her I think you will have to try for guardianship. I would see a qualified elder attorney.

JWB, any chance you could get Dad to use the automated pull from the bank for the utility bills?

If your Dad feels he can only be in control of the checking account there isn't much you can do. Does Dad have a financial Power of Attorney? Is it you, or someone else? If someone else, maybe that person could talk to Dad. There are times when our parents won't listen to us because we are just the kids, and what do we know :P

I had an issue with my Dad throwing out his bills thinking they were junk mail :0

Couldn't Mom just remind him when a bill is coming close to it's due date?

Lololol-"till the emperor has no clothes". That's great Shaking!