What can I do if my 94-year-old mother and her 93-year-old husband are refusing help?

It sounds like it might be a health and safety issue, with the incontinence. If not properly handled, that can cause some medical problems with infection, sores, etc. I'd consider how severe it is and discuss it with your family, their doctor, and make a plan. If anyone has Durable POA and Healthcare POA, they can discuss with their doctor what level of care they need and if outside help could come in to assist them or if they need more. If no one has DPOA and HCPOA, then, I'd consult with an attorney to find out the process for Guardianship. They can advise what evidence you need, costs involved, etc. I'm not one to wait for a crisis. I'd at least explore the options and have a plan in place.

My parents were the same way, they also had refused outside help, nor were they interest in moving into Independent Living. Their stock answer was "we can manage".  Yeah, right, being in their 90's also and living in a house that had stairs.

Usually there isn't anything we can do until a major crises hits... usually someone will have a major fall, 911 is called, hospital, then rehab, then hopefully into senior living. Most places will take couples.

If senior housing isn't in their budget, there is always Medicaid that will help pay for a nursing home, but it doesn't sound like Dad would be ready for that unless he's the one that has the major fall or illness first.