My mom puts "2" Depends on Dad for bedtime but it sometimes still leaks through. She's constantly changing sheets. What works better?

Use both, plus use a large bed pad, either the disposable or the washable kind, directly underneath her. Maybe these will prevent having to change the sheets. Make sure there is a waterproof mattress pad underneath the sheets. You can also use a pad inside the Depend brief. Make sure she wears gowns at night so she/you do not have to constantly change pajama bottoms. If she leaks the sheets, does she go to the bathroom enough during the day, or if she is bedfast, is she on a schedule for bedpan? Does she maybe have a bladder infection if she is going so much?