My husband was just diagnosed with dementia. He is falling and not making it to the bathroom in time. Is this near the end stage?

Elderly people with dementia are at risk for falls but you said, "all of a sudden". I think it's time to take him to the doctor. Any time there is a new symptom it's prudent to follow up with the doctor.

And I agree about encouraging your husband to wear incontinence underwear overnight. Place a pad down beneath him in bed as well. This will help lessen the amount of cleaning you have to do in the middle of the night.

If he was just diagnosed recently and has been fine physically until now you are nowhere near end stage. Do you think he is falling because he is hurrying too fast? It might be helpful to have him wear disposable incontinence underwear at night and to provide a urinal or bedside commode. He might have prostate problems or something else going on, you should mention this to his doctor.