My husband started refusing to shower, which was unusual for him.
I asked a caregiver if she had any ideas. She suggested not calling it a shower or bath but "let's get cleaned up or freshen up."
I think the idea of what I'm asking him to do is overwhelming, so I get in with him to gently prompt him on what to do.
She also suggested no-rinse shampoo and body wash, which I ordered on Amazon.
I put them on a warm washcloth; it helps freshen him up when he won't get in the shower.
There are also no-rinse caps that you put on their heads/hair and massage for a minute or so. These caps clean their hair and scalp without rinsing.
Timing is always important, choosing a time that both of you are up for it.