How do we get Dad in nursing home without Mom's consent?

I don't think you need your mom's permission unless she is specifically named in a healthcare power of attorney or durable power of attorney document. If she is, you need to get that changed ASAP. A NH is going to have to have a POA document on file.

She will have to resign as POA in a legal form to be able to update it with somebody else (like you). You can't just print out a new one (ask me how I know...)

You need a social worker to make a site assessment. This could take time to arrange.

His doctor has to be involved. He can order home health care that will be partly paid by Medicare and the supplemental private insurance. He can also tell dad and mom that NH care is required. Sometimes they listen to the doctor long before they'll listen to us.

You can pursue emergency guardianship, but that is a court maneuver that will require an attorney, and forms from the doctor to certify your father needs guardianship. There will be costs. But this is the fastest way to get guardianship.

Does your mother hold a medical power of attorney for your father? I assume your father isn't able to communicate his needs?

This sounds like an urgent situation. Could you call your father's internist or primary care physician and ask him/her for assistance? Perhaps he could see your father if you can get him via ambulance to the doctors' office for a visit. He might be able to offer some advice on how to get your father to a nursing home.

There's also the possibility of calling EMS to take your father to the ER, and raise the issue with the attending doctor and ask for a social worker consult. An SW can help you locate a nursing facility.

In the meantime I would begin looking at facilities so that you can get your father into one as soon as some medical people get involved to bypass your mother's resistance.

There's an option of contacting APS for immediate assistance, but I suspect your mother would be very unhappy.

Does she normally take care of your father when she's not ill? Are they both living at home, alone, and are you close to them? Is there any other home health aide coming to the home?

Your father's doctor may also order home health care temporarily until the issue of a nursing home placement is worked out.

I honestly don't know of a good way to manage this, but bringing this post forward will alert others who may be able to offer some help.