Just like the ones that will not or do not shower...he has probably forgotten that he showered. Others forget to eat or they eat constantly because they do not remember they have eaten. The concern might be is that he could be drying out his skin. If there is a way that you could redirect him so he does not shower multiple times that might help.
Karlyn, agree with what lealonnie posted. Please remember that slippery bathrooms are not the safest places for seniors. Does he have a shower seat? Does it have grab bars? Does he need to step over a tub to enter it? Do the floors have ample absorbent rugs? Most of all, is some one else present as he is showering?
Well, you have the opposite issue that most find with parents suffering from dementia!! They HATE taking showers & bathing and the care givers find it nearly impossible to convince them to clean up. It sounds like an OCD issue with your dad, which is sometimes prevalent with dementia behaviors. You may want to contact his PCP to see if a mild medication can be prescribed to cut down his anxiety and that may help him to stop bathing & changing so often.
The concern might be is that he could be drying out his skin.
If there is a way that you could redirect him so he does not shower multiple times that might help.
Best of luck!