Here's a few tricks I learned dealing with my dad who has overnight incontinence.
1) No drinking after 6 PM. Anything after 6 PM ends up in the bed in the morning.
2) Bring them to the washroom right before bedtime. Anything that ends up in the bowl is not in the bed in the morning.
3) Consult a doctor/urologist. Sereval pills can give you more control over incontinence. Incontinence has several causes and several medical solutions. Consult a doctor/urologist. Now.
4) Protect your mattress. Buy a vinyl matress protector from Wall-Mart. It's ten bucks. Buy the one that wraps completely around the mattress with a zipper. Buy 2 and put 2 on just to be safe.
5) Catheters. This is the part where your loved ones pees in a bag attached to their leg. Available for both night and day. For males, there are tube catheters and condom catheters. When the diapers don't work, this might save you. Probes also exist, those are only for people who are unable to pee physically.
6) if using diapers, the pull-ups work less well than the diapers with the straps on the side. Consider buying diapers + incontinence pads for extra proctection. Make sure you make holes in the pad so when its full it then leaks into the diaper and not into the bed. You can always put regular underwear after diapers to make things hold better. Speak to a nurse about your loved one to find out what sizes, brands, strategies are best. Nurses are the experts for diapers, not doctors. You have your loved one's privates, then you put on the incontinence pad, then the diapers after and lastly the underwear (in case that wasn't clear).
7) Smell. Don't cover it up get rid of it. Fast. First thing in the morning: Check sheets, wash sheets (buy a thin bed cover to avoid more than 1 load of laundry a day). Wash any washable bed pads in that same load. Throw away diaper in a sealed bag immediately. Make sure loved one is washed. Open the windows.
8) Check for government help in your area. This means services for your loved one. My dad has someone who comes and installs the diaper at night and washes the sheets in the morning every day. This cost me zero dollars. Yes, zero. The government pays. I live in Montreal, Quebec, Canada. Inform yourself, and get whatever information you get confirmed from more than one place. Assume the first person you speak to is wrong. They often are sadly. Double check. Yes, always.
9) Income tax deductions/insurance. Chances are if your loved one is peeing all over the over place, they are probably invalid, incapable of working, or whatever. There are a ton of benefits on income tax and also with insurance compagnies. Check your insurance plan carefully and income tax benefits. Double check the information. I claim diapers on insurance, income tax and social services in Canada. Yes, all 3.
10) If your matress/sofa is soiled and smells after several washes. Throw it out. Buy a new one and protect it.
11) Once again, nurses are the incontinence experts when it comes to diapers and whatnot, not doctors, not social workers. Nurses who do what you now have to do every day, they do it for a living.
12) Don't give up hope. You are not alone. Hope this helps.