There are a wealth of questions on how to get aging parents to bathe – especially when the elderly has Alzheimer's or severe dementia.
One consideration is how often do elderly parents need to bathe? Since the U.S. is a melting pot of people from around the world, we have different cultures with different views on what staying clean means. In my high plains area, many of the generation now in their 80s and 90s grew up with weekly baths – sometimes because they lived out on farms and water was too precious to waste. For others, that routine was just normal behavior. We bratty "kids" would mutter under our breath they would bathe when they were "ripe enough."
All of this is to say that if your elder won't shower every single day, he or she is not going to die of some dreadful disease caused by "lack of bath" syndrome. For some elders, some fairly clean clothes and a weekly bath is what they consider enough. However, there are other issues to consider.
Watch for change in attitude. A change in attitude is a key component with bathing, as it is with many aging issues.
Is the change in bathing habits due to memory loss, confusion or fear?
If your elder has dementia, then you may have a more difficult situation on your hands. People can think they have just showered, but in reality that was last week. Or, they can become confused when they begin the process, and rather than tell someone they are confused, they just avoid it. Or they can become afraid of the shower or bath because they don't know what it's all about or they think they will get hurt.
Think about how frightening it would be to have water pouring down on your head when you can't figure out the reason. Confusion and lack of understanding are bound to lead to fear.