I had sort of the opposite problem with the Wife, she got upset that she can not brush and floss like she use to.
she switch to a cheap spinning bristle brush for a while and I used those floss with a holder things while she laid in bed (for several years).
recently, We had to switch dentist, but I was able to find one that will just "brush" her teeth every couple weeks using a block to keep her mouth open and an assistant with spray and suction