How to keep water away from ears in shower?

When I wash my dad's hair in the shower I have yet to find a satisfactory way to prevent water from entering his ears when rinsing the shampoo from his hair.
There are some creative solutions available for children but never for an adult sized head despite what some may claim.
*Side note: My mother was helping him with his shower previously and
I would often hear him holler about water getting in his ears.
She told me she gives give him two dry wash cloths and tells
him to cover his ears with them while she quickly rinses his
hair. She said somehow water still gets in his ears! During his
next shower I was there helping when he started hollering
about water getting in ears. I glanced over as my mom was
nervously rinsing his hair. She didn't seem to notice my dad
was holding the wash cloths firmly only over his eyes! When
I pointed this out to her she looked at me for a few seconds
realizing this was why water was always getting in his ears
each time! She gently guided my dads hands so that the wash
cloths covered his ears and started to laugh (thank goodness)
and then so could I. When my dad said "What's so funny?" all
we could do was laugh some more.