My husband is 79 years old, vascular dementia with deep white matter disease. Please also check with your husband’s PCP, my husband’s does not want him to undergo anesthesia, if at all possible, due to its physical effects on the brains of those with dementia.
His dentist has been very helpful in providing care and the female hygienist is key to getting him laughing and relaxed. They use the x-ray machine intended for those with special needs (it’s like a box he sits inside).
My husband is also more willing if I pair the visit with something he likes afterwards- usually promising a visit to Harbor Freight or Perkins and (yes) if needed, telling him if he doesn’t cooperate, it’s back to home.
Best of luck to you, it’s hard.